diff --git a/c/qrcodegen-demo.c b/c/qrcodegen-demo.c
index aee3064..36cdec3 100644
--- a/c/qrcodegen-demo.c
+++ b/c/qrcodegen-demo.c
@@ -36,6 +36,7 @@
 static void doBasicDemo(void);
 static void doVarietyDemo(void);
 static void doSegmentDemo(void);
+static void doMaskDemo(void);
 static void printQr(const uint8_t qrcode[]);
 
 
@@ -45,6 +46,7 @@ int main(void) {
 	doBasicDemo();
 	doVarietyDemo();
 	doSegmentDemo();
+	doMaskDemo();
 	return EXIT_SUCCESS;
 }
 
@@ -66,15 +68,6 @@ static void doBasicDemo(void) {
 
 // Creates a variety of QR Codes that exercise different features of the library, and prints each one to the console.
 static void doVarietyDemo(void) {
-	{  // Project Nayuki URL
-		uint8_t qrcode[qrcodegen_BUFFER_LEN_MAX];
-		uint8_t tempBuffer[qrcodegen_BUFFER_LEN_MAX];
-		bool ok = qrcodegen_encodeText("https://www.nayuki.io/", tempBuffer, qrcode,
-			qrcodegen_Ecc_HIGH, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_3, true);
-		if (ok)
-			printQr(qrcode);
-	}
-	
 	{  // Numeric mode encoding (3.33 bits per digit)
 		uint8_t qrcode[qrcodegen_BUFFER_LEN_MAX];
 		uint8_t tempBuffer[qrcodegen_BUFFER_LEN_MAX];
@@ -93,29 +86,12 @@ static void doVarietyDemo(void) {
 			printQr(qrcode);
 	}
 	
-	{  // Unicode text as UTF-8, and different masks
+	{  // Unicode text as UTF-8
 		const char *text = "\xE3\x81\x93\xE3\x82\x93\xE3\x81\xAB\xE3\x81\xA1wa\xE3\x80\x81\xE4\xB8\x96\xE7\x95\x8C\xEF\xBC\x81\x20\xCE\xB1\xCE\xB2\xCE\xB3\xCE\xB4";
 		uint8_t qrcode[qrcodegen_BUFFER_LEN_MAX];
 		uint8_t tempBuffer[qrcodegen_BUFFER_LEN_MAX];
-		bool ok;
-		
-		ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
-			qrcodegen_Ecc_QUARTILE, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_0, true);
-		if (ok)
-			printQr(qrcode);
-		
-		ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
-			qrcodegen_Ecc_QUARTILE, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_1, true);
-		if (ok)
-			printQr(qrcode);
-		
-		ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
-			qrcodegen_Ecc_QUARTILE, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_5, true);
-		if (ok)
-			printQr(qrcode);
-		
-		ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
-			qrcodegen_Ecc_QUARTILE, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_7, true);
+		bool ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
+			qrcodegen_Ecc_QUARTILE, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_AUTO, true);
 		if (ok)
 			printQr(qrcode);
 	}
@@ -260,6 +236,60 @@ static void doSegmentDemo(void) {
 }
 
 
+// Creates QR Codes with the same size and contents but different mask patterns.
+static void doMaskDemo(void) {
+	{  // Project Nayuki URL
+		uint8_t qrcode[qrcodegen_BUFFER_LEN_MAX];
+		uint8_t tempBuffer[qrcodegen_BUFFER_LEN_MAX];
+		bool ok;
+		
+		ok = qrcodegen_encodeText("https://www.nayuki.io/", tempBuffer, qrcode,
+			qrcodegen_Ecc_HIGH, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_AUTO, true);
+		if (ok)
+			printQr(qrcode);
+		
+		ok = qrcodegen_encodeText("https://www.nayuki.io/", tempBuffer, qrcode,
+			qrcodegen_Ecc_HIGH, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_3, true);
+		if (ok)
+			printQr(qrcode);
+	}
+	
+	{  // Chinese text as UTF-8
+		const char *text =
+			"\xE7\xB6\xAD\xE5\x9F\xBA\xE7\x99\xBE\xE7\xA7\x91\xEF\xBC\x88\x57\x69\x6B\x69\x70"
+			"\x65\x64\x69\x61\xEF\xBC\x8C\xE8\x81\x86\xE8\x81\xBD\x69\x2F\xCB\x8C\x77\xC9\xAA"
+			"\x6B\xE1\xB5\xBB\xCB\x88\x70\x69\xCB\x90\x64\x69\x2E\xC9\x99\x2F\xEF\xBC\x89\xE6"
+			"\x98\xAF\xE4\xB8\x80\xE5\x80\x8B\xE8\x87\xAA\xE7\x94\xB1\xE5\x85\xA7\xE5\xAE\xB9"
+			"\xE3\x80\x81\xE5\x85\xAC\xE9\x96\x8B\xE7\xB7\xA8\xE8\xBC\xAF\xE4\xB8\x94\xE5\xA4"
+			"\x9A\xE8\xAA\x9E\xE8\xA8\x80\xE7\x9A\x84\xE7\xB6\xB2\xE8\xB7\xAF\xE7\x99\xBE\xE7"
+			"\xA7\x91\xE5\x85\xA8\xE6\x9B\xB8\xE5\x8D\x94\xE4\xBD\x9C\xE8\xA8\x88\xE7\x95\xAB";
+		uint8_t qrcode[qrcodegen_BUFFER_LEN_MAX];
+		uint8_t tempBuffer[qrcodegen_BUFFER_LEN_MAX];
+		bool ok;
+		
+		ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
+			qrcodegen_Ecc_MEDIUM, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_0, true);
+		if (ok)
+			printQr(qrcode);
+		
+		ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
+			qrcodegen_Ecc_MEDIUM, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_1, true);
+		if (ok)
+			printQr(qrcode);
+		
+		ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
+			qrcodegen_Ecc_MEDIUM, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_5, true);
+		if (ok)
+			printQr(qrcode);
+		
+		ok = qrcodegen_encodeText(text, tempBuffer, qrcode,
+			qrcodegen_Ecc_MEDIUM, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_7, true);
+		if (ok)
+			printQr(qrcode);
+	}
+}
+
+
 // Prints the given QR Code to the console.
 static void printQr(const uint8_t qrcode[]) {
 	int size = qrcodegen_getSize(qrcode);
diff --git a/cpp/QrCode.cpp b/cpp/QrCode.cpp
index bad055a..ef73d54 100644
--- a/cpp/QrCode.cpp
+++ b/cpp/QrCode.cpp
@@ -139,25 +139,6 @@ QrCode::QrCode(int ver, Ecc ecl, const vector<uint8_t> &dataCodewords, int mask)
 }
 
 
-QrCode::QrCode(const QrCode &qr, int mask) :
-		// Copy scalar fields
-		version(qr.version),
-		size(qr.size),
-		errorCorrectionLevel(qr.errorCorrectionLevel),
-		// Handle grid fields
-		modules(qr.modules),
-		isFunction(qr.isFunction) {
-	
-	// Check arguments
-	if (mask < -1 || mask > 7)
-		throw "Mask value out of range";
-	
-	// Handle masking
-	applyMask(qr.mask);  // Undo old mask
-	this->mask = handleConstructorMasking(mask);
-}
-
-
 int QrCode::getVersion() const {
 	return version;
 }
diff --git a/cpp/QrCode.hpp b/cpp/QrCode.hpp
index d7d050d..688e70a 100644
--- a/cpp/QrCode.hpp
+++ b/cpp/QrCode.hpp
@@ -132,14 +132,6 @@ class QrCode final {
 	public: QrCode(int ver, Ecc ecl, const std::vector<std::uint8_t> &dataCodewords, int mask);
 	
 	
-	/* 
-	 * Creates a new QR Code symbol based on the given existing object, but with a potentially
-	 * different mask pattern. The version, error correction level, codewords, etc. of the newly
-	 * created object are all identical to the argument object; only the mask may differ.
-	 */
-	public: QrCode(const QrCode &qr, int mask);
-	
-	
 	
 	/*---- Public instance methods ----*/
 	
diff --git a/cpp/QrCodeGeneratorDemo.cpp b/cpp/QrCodeGeneratorDemo.cpp
index fc124f5..63951e4 100644
--- a/cpp/QrCodeGeneratorDemo.cpp
+++ b/cpp/QrCodeGeneratorDemo.cpp
@@ -42,6 +42,7 @@ using qrcodegen::QrSegment;
 static void doBasicDemo();
 static void doVarietyDemo();
 static void doSegmentDemo();
+static void doMaskDemo();
 static void printQr(const QrCode &qr);
 
 
@@ -51,6 +52,7 @@ int main() {
 	doBasicDemo();
 	doVarietyDemo();
 	doSegmentDemo();
+	doMaskDemo();
 	return EXIT_SUCCESS;
 }
 
@@ -69,10 +71,6 @@ static void doBasicDemo() {
 
 // Creates a variety of QR Codes that exercise different features of the library, and prints each one to the console.
 static void doVarietyDemo() {
-	// Project Nayuki URL
-	const QrCode qr0 = QrCode::encodeText("https://www.nayuki.io/", QrCode::Ecc::HIGH);
-	printQr(QrCode(qr0, 3));  // Change mask, forcing to mask #3
-	
 	// Numeric mode encoding (3.33 bits per digit)
 	const QrCode qr1 = QrCode::encodeText("314159265358979323846264338327950288419716939937510", QrCode::Ecc::MEDIUM);
 	printQr(qr1);
@@ -81,12 +79,9 @@ static void doVarietyDemo() {
 	const QrCode qr2 = QrCode::encodeText("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", QrCode::Ecc::HIGH);
 	printQr(qr2);
 	
-	// Unicode text as UTF-8, and different masks
+	// Unicode text as UTF-8
 	const QrCode qr3 = QrCode::encodeText("\xE3\x81\x93\xE3\x82\x93\xE3\x81\xAB\xE3\x81\xA1wa\xE3\x80\x81\xE4\xB8\x96\xE7\x95\x8C\xEF\xBC\x81\x20\xCE\xB1\xCE\xB2\xCE\xB3\xCE\xB4", QrCode::Ecc::QUARTILE);
-	printQr(QrCode(qr3, 0));
-	printQr(QrCode(qr3, 1));
-	printQr(QrCode(qr3, 5));
-	printQr(QrCode(qr3, 7));
+	printQr(qr3);
 	
 	// Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
 	const QrCode qr4 = QrCode::encodeText(
@@ -163,6 +158,29 @@ static void doSegmentDemo() {
 }
 
 
+// Creates QR Codes with the same size and contents but different mask patterns.
+static void doMaskDemo() {
+	// Project Nayuki URL
+	std::vector<QrSegment> segs0 = QrSegment::makeSegments("https://www.nayuki.io/");
+	printQr(QrCode::encodeSegments(segs0, QrCode::Ecc::HIGH, 1, 40, -1, true));  // Automatic mask
+	printQr(QrCode::encodeSegments(segs0, QrCode::Ecc::HIGH, 1, 40, 3, true));  // Force mask 3
+	
+	// Chinese text as UTF-8
+	std::vector<QrSegment> segs1 = QrSegment::makeSegments(
+		"\xE7\xB6\xAD\xE5\x9F\xBA\xE7\x99\xBE\xE7\xA7\x91\xEF\xBC\x88\x57\x69\x6B\x69\x70"
+		"\x65\x64\x69\x61\xEF\xBC\x8C\xE8\x81\x86\xE8\x81\xBD\x69\x2F\xCB\x8C\x77\xC9\xAA"
+		"\x6B\xE1\xB5\xBB\xCB\x88\x70\x69\xCB\x90\x64\x69\x2E\xC9\x99\x2F\xEF\xBC\x89\xE6"
+		"\x98\xAF\xE4\xB8\x80\xE5\x80\x8B\xE8\x87\xAA\xE7\x94\xB1\xE5\x85\xA7\xE5\xAE\xB9"
+		"\xE3\x80\x81\xE5\x85\xAC\xE9\x96\x8B\xE7\xB7\xA8\xE8\xBC\xAF\xE4\xB8\x94\xE5\xA4"
+		"\x9A\xE8\xAA\x9E\xE8\xA8\x80\xE7\x9A\x84\xE7\xB6\xB2\xE8\xB7\xAF\xE7\x99\xBE\xE7"
+		"\xA7\x91\xE5\x85\xA8\xE6\x9B\xB8\xE5\x8D\x94\xE4\xBD\x9C\xE8\xA8\x88\xE7\x95\xAB");
+	printQr(QrCode::encodeSegments(segs1, QrCode::Ecc::MEDIUM, 1, 40, 0, true));  // Force mask 0
+	printQr(QrCode::encodeSegments(segs1, QrCode::Ecc::MEDIUM, 1, 40, 1, true));  // Force mask 1
+	printQr(QrCode::encodeSegments(segs1, QrCode::Ecc::MEDIUM, 1, 40, 5, true));  // Force mask 5
+	printQr(QrCode::encodeSegments(segs1, QrCode::Ecc::MEDIUM, 1, 40, 7, true));  // Force mask 7
+}
+
+
 // Prints the given QR Code to the console.
 static void printQr(const QrCode &qr) {
 	int border = 4;
diff --git a/java/io/nayuki/qrcodegen/QrCode.java b/java/io/nayuki/qrcodegen/QrCode.java
index 76bfa81..7495d44 100644
--- a/java/io/nayuki/qrcodegen/QrCode.java
+++ b/java/io/nayuki/qrcodegen/QrCode.java
@@ -222,38 +222,6 @@ public final class QrCode {
 	}
 	
 	
-	/**
-	 * Creates a new QR Code symbol based on the specified existing object, but with a potentially
-	 * different mask pattern. The version, error correction level, codewords, etc. of the newly
-	 * created object are all identical to the argument object; only the mask may differ.
-	 * @param qr the existing QR Code to copy and modify
-	 * @param mask the new mask pattern, 0 to 7 to force a fixed choice or -1 for an automatic choice
-	 * @throws NullPointerException if the QR Code is {@code null}
-	 * @throws IllegalArgumentException if the mask value is out of range
-	 */
-	public QrCode(QrCode qr, int mask) {
-		// Check arguments
-		Objects.requireNonNull(qr);
-		if (mask < -1 || mask > 7)
-			throw new IllegalArgumentException("Mask value out of range");
-		
-		// Copy scalar fields
-		version = qr.version;
-		size = qr.size;
-		errorCorrectionLevel = qr.errorCorrectionLevel;
-		
-		// Handle grid fields
-		isFunction = qr.isFunction;  // Shallow copy because the data is read-only
-		modules = qr.modules.clone();  // Deep copy
-		for (int i = 0; i < modules.length; i++)
-			modules[i] = modules[i].clone();
-		
-		// Handle masking
-		applyMask(qr.mask);  // Undo old mask
-		this.mask = handleConstructorMasking(mask);
-	}
-	
-	
 	
 	/*---- Public instance methods ----*/
 	
diff --git a/java/io/nayuki/qrcodegen/QrCodeGeneratorDemo.java b/java/io/nayuki/qrcodegen/QrCodeGeneratorDemo.java
index c9d5dfd..ba54148 100644
--- a/java/io/nayuki/qrcodegen/QrCodeGeneratorDemo.java
+++ b/java/io/nayuki/qrcodegen/QrCodeGeneratorDemo.java
@@ -45,6 +45,7 @@ public final class QrCodeGeneratorDemo {
 		doBasicDemo();
 		doVarietyDemo();
 		doSegmentDemo();
+		doMaskDemo();
 	}
 	
 	
@@ -72,11 +73,6 @@ public final class QrCodeGeneratorDemo {
 	private static void doVarietyDemo() throws IOException {
 		QrCode qr;
 		
-		// Project Nayuki URL
-		qr = QrCode.encodeText("https://www.nayuki.io/", QrCode.Ecc.HIGH);
-		qr = new QrCode(qr, 3);  // Change mask, forcing to mask #3
-		writePng(qr.toImage(8, 6), "project-nayuki-QR.png");
-		
 		// Numeric mode encoding (3.33 bits per digit)
 		qr = QrCode.encodeText("314159265358979323846264338327950288419716939937510", QrCode.Ecc.MEDIUM);
 		writePng(qr.toImage(13, 1), "pi-digits-QR.png");
@@ -85,12 +81,9 @@ public final class QrCodeGeneratorDemo {
 		qr = QrCode.encodeText("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", QrCode.Ecc.HIGH);
 		writePng(qr.toImage(10, 2), "alphanumeric-QR.png");
 		
-		// Unicode text as UTF-8, and different masks
+		// Unicode text as UTF-8
 		qr = QrCode.encodeText("こんにちwa、世界！ αβγδ", QrCode.Ecc.QUARTILE);
-		writePng(new QrCode(qr, 0).toImage(10, 3), "unicode-mask0-QR.png");
-		writePng(new QrCode(qr, 1).toImage(10, 3), "unicode-mask1-QR.png");
-		writePng(new QrCode(qr, 5).toImage(10, 3), "unicode-mask5-QR.png");
-		writePng(new QrCode(qr, 7).toImage(10, 3), "unicode-mask7-QR.png");
+		writePng(qr.toImage(10, 3), "unicode-QR.png");
 		
 		// Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
 		qr = QrCode.encodeText(
@@ -158,6 +151,31 @@ public final class QrCodeGeneratorDemo {
 	}
 	
 	
+	// Creates QR Codes with the same size and contents but different mask patterns.
+	private static void doMaskDemo() throws IOException {
+		QrCode qr;
+		List<QrSegment> segs;
+		
+		// Project Nayuki URL
+		segs = QrSegment.makeSegments("https://www.nayuki.io/");
+		qr = QrCode.encodeSegments(segs, QrCode.Ecc.HIGH, 1, 40, -1, true);  // Automatic mask
+		writePng(qr.toImage(8, 6), "project-nayuki-automask-QR.png");
+		qr = QrCode.encodeSegments(segs, QrCode.Ecc.HIGH, 1, 40, 3, true);  // Force mask 3
+		writePng(qr.toImage(8, 6), "project-nayuki-mask3-QR.png");
+		
+		// Chinese text as UTF-8
+		segs = QrSegment.makeSegments("維基百科（Wikipedia，聆聽i/ˌwɪkᵻˈpiːdi.ə/）是一個自由內容、公開編輯且多語言的網路百科全書協作計畫");
+		qr = QrCode.encodeSegments(segs, QrCode.Ecc.MEDIUM, 1, 40, 0, true);  // Force mask 0
+		writePng(qr.toImage(10, 3), "unicode-mask0-QR.png");
+		qr = QrCode.encodeSegments(segs, QrCode.Ecc.MEDIUM, 1, 40, 1, true);  // Force mask 1
+		writePng(qr.toImage(10, 3), "unicode-mask1-QR.png");
+		qr = QrCode.encodeSegments(segs, QrCode.Ecc.MEDIUM, 1, 40, 5, true);  // Force mask 5
+		writePng(qr.toImage(10, 3), "unicode-mask5-QR.png");
+		qr = QrCode.encodeSegments(segs, QrCode.Ecc.MEDIUM, 1, 40, 7, true);  // Force mask 7
+		writePng(qr.toImage(10, 3), "unicode-mask7-QR.png");
+	}
+	
+	
 	// Helper function to reduce code duplication.
 	private static void writePng(BufferedImage img, String filepath) throws IOException {
 		ImageIO.write(img, "png", new File(filepath));
diff --git a/javascript/qrcodegen.js b/javascript/qrcodegen.js
index 3115097..e2fc53e 100644
--- a/javascript/qrcodegen.js
+++ b/javascript/qrcodegen.js
@@ -31,7 +31,6 @@
  *   - Function encodeBinary(list<byte> data, QrCode.Ecc ecl) -> QrCode
  *   - Function encodeSegments(list<QrSegment> segs, QrCode.Ecc ecl,
  *         int minVersion=1, int maxVersion=40, mask=-1, boostEcl=true) -> QrCode
- *   - Constructor QrCode(QrCode qr, int mask)
  *   - Constructor QrCode(list<int> datacodewords, int mask, int version, QrCode.Ecc ecl)
  *   - Fields int version, size, mask
  *   - Field QrCode.Ecc errorCorrectionLevel
@@ -64,35 +63,19 @@ var qrcodegen = new function() {
 	 * with associated static functions to create a QR Code from user-supplied textual or binary data.
 	 * This class covers the QR Code model 2 specification, supporting all versions (sizes)
 	 * from 1 to 40, all 4 error correction levels.
-	 * 
-	 * This constructor can be called in one of two ways:
-	 * - new QrCode(datacodewords, mask, version, errCorLvl):
-	 *       Creates a new QR Code symbol with the given version number, error correction level, binary data array,
-	 *       and mask number. This is a cumbersome low-level constructor that should not be invoked directly by the user.
-	 *       To go one level up, see the QrCode.encodeSegments() function.
-	 * - new QrCode(qr, mask):
-	 *       Creates a new QR Code symbol based on the given existing object, but with a potentially different
-	 *       mask pattern. The version, error correction level, codewords, etc. of the newly created object are
-	 *       all identical to the argument object; only the mask may differ.
-	 * In both cases, mask = -1 is for automatic choice or 0 to 7 for fixed choice.
+	 * This constructor creates a new QR Code symbol with the given version number, error correction level, binary data array,
+	 * and mask number. mask = -1 is for automatic choice, or 0 to 7 for fixed choice. This is a cumbersome low-level constructor
+	 * that should not be invoked directly by the user. To go one level up, see the QrCode.encodeSegments() function.
 	 */
-	this.QrCode = function(initData, mask, version, errCorLvl) {
+	this.QrCode = function(datacodewords, mask, version, errCorLvl) {
 		
 		/*---- Constructor ----*/
 		
 		// Check arguments and handle simple scalar fields
 		if (mask < -1 || mask > 7)
 			throw "Mask value out of range";
-		if (initData instanceof Array) {
-			if (version < 1 || version > 40)
-				throw "Version value out of range";
-		} else if (initData instanceof qrcodegen.QrCode) {
-			if (version != undefined || errCorLvl != undefined)
-				throw "Values must be undefined";
-			version = initData.version;
-			errCorLvl = initData.errorCorrectionLevel;
-		} else
-			throw "Invalid initial data";
+		if (version < 1 || version > 40)
+			throw "Version value out of range";
 		var size = version * 4 + 17;
 		
 		// Initialize both grids to be size*size arrays of Boolean false
@@ -106,22 +89,10 @@ var qrcodegen = new function() {
 			isFunction.push(row.slice());
 		}
 		
-		// Handle grid fields
-		if (initData instanceof Array) {
-			// Draw function patterns, draw all codewords
-			drawFunctionPatterns();
-			var allCodewords = appendErrorCorrection(initData);
-			drawCodewords(allCodewords);
-		} else if (initData instanceof qrcodegen.QrCode) {
-			for (var y = 0; y < size; y++) {
-				for (var x = 0; x < size; x++) {
-					modules[y][x] = initData.getModule(x, y);
-					isFunction[y][x] = initData.isFunctionModule(x, y);
-				}
-			}
-			applyMask(initData.mask);  // Undo old mask
-		} else
-			throw "Invalid initial data";
+		// Handle grid fields, draw function patterns, draw all codewords
+		drawFunctionPatterns();
+		var allCodewords = appendErrorCorrection(datacodewords);
+		drawCodewords(allCodewords);
 		
 		// Handle masking
 		if (mask == -1) {  // Automatically choose best mask
diff --git a/python/qrcodegen-demo.py b/python/qrcodegen-demo.py
index 035820d..9db5c1f 100644
--- a/python/qrcodegen-demo.py
+++ b/python/qrcodegen-demo.py
@@ -35,6 +35,7 @@ def main():
 	do_basic_demo()
 	do_variety_demo()
 	do_segment_demo()
+	do_mask_demo()
 
 
 def do_basic_demo():
@@ -51,11 +52,6 @@ def do_basic_demo():
 def do_variety_demo():
 	"""Creates a variety of QR Codes that exercise different features of the library, and prints each one to the console."""
 	
-	# Project Nayuki URL
-	qr = qrcodegen.QrCode.encode_text("https://www.nayuki.io/", qrcodegen.QrCode.Ecc.HIGH)
-	qr = qrcodegen.QrCode(qrcode=qr, mask=3)  # Change mask, forcing to mask #3
-	print_qr(qr)
-	
 	# Numeric mode encoding (3.33 bits per digit)
 	qr = qrcodegen.QrCode.encode_text("314159265358979323846264338327950288419716939937510", qrcodegen.QrCode.Ecc.MEDIUM)
 	print_qr(qr)
@@ -64,12 +60,9 @@ def do_variety_demo():
 	qr = qrcodegen.QrCode.encode_text("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", qrcodegen.QrCode.Ecc.HIGH)
 	print_qr(qr)
 	
-	# Unicode text as UTF-8, and different masks
+	# Unicode text as UTF-8
 	qr = qrcodegen.QrCode.encode_text(u"\u3053\u3093\u306B\u3061\u0077\u0061\u3001\u4E16\u754C\uFF01\u0020\u03B1\u03B2\u03B3\u03B4", qrcodegen.QrCode.Ecc.QUARTILE)
-	print_qr(qrcodegen.QrCode(qrcode=qr, mask=0))
-	print_qr(qrcodegen.QrCode(qrcode=qr, mask=1))
-	print_qr(qrcodegen.QrCode(qrcode=qr, mask=5))
-	print_qr(qrcodegen.QrCode(qrcode=qr, mask=7))
+	print_qr(qr)
 	
 	# Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
 	qr = qrcodegen.QrCode.encode_text(
@@ -153,6 +146,27 @@ def do_segment_demo():
 	print_qr(qr)
 
 
+def do_mask_demo():
+	"""Creates QR Codes with the same size and contents but different mask patterns."""
+	
+	# Project Nayuki URL
+	segs = qrcodegen.QrSegment.make_segments("https://www.nayuki.io/")
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.HIGH, mask=-1))  # Automatic mask
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.HIGH, mask=3))  # Force mask 3
+	
+	# Chinese text as UTF-8
+	segs = qrcodegen.QrSegment.make_segments(
+		u"\u7DAD\u57FA\u767E\u79D1\uFF08\u0057\u0069\u006B\u0069\u0070\u0065\u0064\u0069\u0061\uFF0C"
+		 "\u8046\u807D\u0069\u002F\u02CC\u0077\u026A\u006B\u1D7B\u02C8\u0070\u0069\u02D0\u0064\u0069"
+		 "\u002E\u0259\u002F\uFF09\u662F\u4E00\u500B\u81EA\u7531\u5167\u5BB9\u3001\u516C\u958B\u7DE8"
+		 "\u8F2F\u4E14\u591A\u8A9E\u8A00\u7684\u7DB2\u8DEF\u767E\u79D1\u5168\u66F8\u5354\u4F5C\u8A08"
+		 "\u756B")
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.MEDIUM, mask=0))  # Force mask 0
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.MEDIUM, mask=1))  # Force mask 1
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.MEDIUM, mask=5))  # Force mask 5
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.MEDIUM, mask=7))  # Force mask 7
+
+
 
 # ---- Utilities ----
 
diff --git a/python/qrcodegen.py b/python/qrcodegen.py
index b175ce8..1d90bdc 100644
--- a/python/qrcodegen.py
+++ b/python/qrcodegen.py
@@ -31,7 +31,6 @@ This module "qrcodegen", public members:
   - Function encode_binary(bytes data, QrCode.Ecc ecl) -> QrCode
   - Function encode_segments(list<QrSegment> segs, QrCode.Ecc ecl,
         int minversion=1, int maxversion=40, mask=-1, boostecl=true) -> QrCode
-  - Constructor QrCode(QrCode qr, int mask)
   - Constructor QrCode(bytes datacodewords, int mask, int version, QrCode.Ecc ecl)
   - Method get_version() -> int
   - Method get_size() -> int
@@ -135,56 +134,36 @@ class QrCode(object):
 		assert len(bb) % 8 == 0
 		
 		# Create the QR Code symbol
-		return QrCode(None, bb.get_bytes(), mask, version, ecl)
+		return QrCode(bb.get_bytes(), mask, version, ecl)
 	
 	
 	# ---- Constructor ----
 	
-	def __init__(self, qrcode=None, datacodewords=None, mask=None, version=None, errcorlvl=None):
-		"""This constructor can be called in one of two ways:
-		- QrCode(datacodewords=list<int>, mask=int, version=int, errcorlvl=QrCode.Ecc):
-		      Creates a new QR Code symbol with the given version number, error correction level, binary data array,
-		      and mask number. This is a cumbersome low-level constructor that should not be invoked directly by the user.
-		      To go one level up, see the QrCode.encode_segments() function.
-		- QrCode(qrcode=QrCode, mask=int):
-		      Creates a new QR Code symbol based on the given existing object, but with a potentially different
-		      mask pattern. The version, error correction level, codewords, etc. of the newly created object are
-		      all identical to the argument object; only the mask may differ.
-		In both cases, mask = -1 is for automatic choice or 0 to 7 for fixed choice."""
+	def __init__(self, datacodewords, mask, version, errcorlvl):
+		"""Creates a new QR Code symbol with the given version number, error correction level, binary data array,
+		and mask number. mask = -1 is for automatic choice, or 0 to 7 for fixed choice. This is a cumbersome low-level constructor
+		that should not be invoked directly by the user. To go one level up, see the QrCode.encode_segments() function."""
 		
 		# Check arguments and handle simple scalar fields
 		if not (-1 <= mask <= 7):
 			raise ValueError("Mask value out of range")
-		if datacodewords is not None and qrcode is None:
-			if not (1 <= version <= 40):
-				raise ValueError("Version value out of range")
-			if not isinstance(errcorlvl, QrCode.Ecc):
-				raise TypeError("QrCode.Ecc expected")
-		elif qrcode is not None and datacodewords is None:
-			if version is not None or errcorlvl is not None:
-				raise ValueError("Values must be None")
-			version = qrcode._version
-			errcorlvl = qrcode._errcorlvl
-		else:
-			raise ValueError("Exactly one of datacodewords or qrcode must be not None")
+		if not (1 <= version <= 40):
+			raise ValueError("Version value out of range")
+		if not isinstance(errcorlvl, QrCode.Ecc):
+			raise TypeError("QrCode.Ecc expected")
 		self._version = version
 		self._errcorlvl = errcorlvl
 		self._size = version * 4 + 17
 		
-		if datacodewords is not None:  # Render from scratch a QR Code based on data codewords
-			if len(datacodewords) != QrCode._get_num_data_codewords(version, errcorlvl):
-				raise ValueError("Invalid array length")
-			# Initialize grids of modules
-			self._modules    = [[False] * self._size for _ in range(self._size)]  # The modules of the QR symbol; start with entirely white grid
-			self._isfunction = [[False] * self._size for _ in range(self._size)]  # Indicates function modules that are not subjected to masking
-			# Draw function patterns, draw all codewords
-			self._draw_function_patterns()
-			allcodewords = self._append_error_correction(datacodewords)
-			self._draw_codewords(allcodewords)
-		elif qrcode is not None:  # Modify the mask of an existing QR Code
-			self._modules = [list(row) for row in qrcode._modules]  # Deep copy
-			self._isfunction = qrcode._isfunction  # Shallow copy because the data is read-only
-			self._apply_mask(qrcode._mask)  # Undo existing mask
+		if len(datacodewords) != QrCode._get_num_data_codewords(version, errcorlvl):
+			raise ValueError("Invalid array length")
+		# Initialize grids of modules
+		self._modules    = [[False] * self._size for _ in range(self._size)]  # The modules of the QR symbol; start with entirely white grid
+		self._isfunction = [[False] * self._size for _ in range(self._size)]  # Indicates function modules that are not subjected to masking
+		# Draw function patterns, draw all codewords
+		self._draw_function_patterns()
+		allcodewords = self._append_error_correction(datacodewords)
+		self._draw_codewords(allcodewords)
 		
 		# Handle masking
 		if mask == -1:  # Automatically choose best mask
diff --git a/rust/examples/qrcodegen-demo.rs b/rust/examples/qrcodegen-demo.rs
index 069d491..ec1f535 100644
--- a/rust/examples/qrcodegen-demo.rs
+++ b/rust/examples/qrcodegen-demo.rs
@@ -35,6 +35,7 @@ fn main() {
 	do_basic_demo();
 	do_variety_demo();
 	do_segment_demo();
+	do_mask_demo();
 }
 
 
@@ -52,11 +53,6 @@ fn do_basic_demo() {
 
 // Creates a variety of QR Codes that exercise different features of the library, and prints each one to the console.
 fn do_variety_demo() {
-	// Project Nayuki URL
-	let qr = QrCode::encode_text("https://www.nayuki.io/", QrCodeEcc::High).unwrap();
-	let qr = QrCode::remask(&qr, Some(3));  // Change mask, forcing to mask #3
-	print_qr(&qr);
-	
 	// Numeric mode encoding (3.33 bits per digit)
 	let qr = QrCode::encode_text("314159265358979323846264338327950288419716939937510", QrCodeEcc::Medium).unwrap();
 	print_qr(&qr);
@@ -65,12 +61,9 @@ fn do_variety_demo() {
 	let qr = QrCode::encode_text("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", QrCodeEcc::High).unwrap();
 	print_qr(&qr);
 	
-	// Unicode text as UTF-8, and different masks
+	// Unicode text as UTF-8
 	let qr = QrCode::encode_text("こんにちwa、世界！ αβγδ", QrCodeEcc::Quartile).unwrap();
-	print_qr(&QrCode::remask(&qr, Some(0)));
-	print_qr(&QrCode::remask(&qr, Some(1)));
-	print_qr(&QrCode::remask(&qr, Some(5)));
-	print_qr(&QrCode::remask(&qr, Some(7)));
+	print_qr(&qr);
 	
 	// Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
 	let qr = QrCode::encode_text(concat!(
@@ -140,6 +133,28 @@ fn do_segment_demo() {
 }
 
 
+// Creates QR Codes with the same size and contents but different mask patterns.
+fn do_mask_demo() {
+	// Project Nayuki URL
+	let segs = QrSegment::make_segments(&to_chars("https://www.nayuki.io/"));
+	let qr = QrCode::encode_segments_advanced(&segs, QrCodeEcc::High, 1, 40, None, true).unwrap();  // Automatic mask
+	print_qr(&qr);
+	let qr = QrCode::encode_segments_advanced(&segs, QrCodeEcc::High, 1, 40, Some(3), true).unwrap();  // Force mask 3
+	print_qr(&qr);
+	
+	// Chinese text as UTF-8
+	let segs = QrSegment::make_segments(&to_chars("維基百科（Wikipedia，聆聽i/ˌwɪkᵻˈpiːdi.ə/）是一個自由內容、公開編輯且多語言的網路百科全書協作計畫"));
+	let qr = QrCode::encode_segments_advanced(&segs, QrCodeEcc::Medium, 1, 40, Some(0), true).unwrap();  // Force mask 0
+	print_qr(&qr);
+	let qr = QrCode::encode_segments_advanced(&segs, QrCodeEcc::Medium, 1, 40, Some(1), true).unwrap();  // Force mask 1
+	print_qr(&qr);
+	let qr = QrCode::encode_segments_advanced(&segs, QrCodeEcc::Medium, 1, 40, Some(5), true).unwrap();  // Force mask 5
+	print_qr(&qr);
+	let qr = QrCode::encode_segments_advanced(&segs, QrCodeEcc::Medium, 1, 40, Some(7), true).unwrap();  // Force mask 7
+	print_qr(&qr);
+}
+
+
 /*---- Utilities ----*/
 
 // Prints the given QrCode object to the console.
diff --git a/rust/src/lib.rs b/rust/src/lib.rs
index 1a6696d..c33945d 100644
--- a/rust/src/lib.rs
+++ b/rust/src/lib.rs
@@ -193,30 +193,6 @@ impl QrCode {
 	}
 	
 	
-	// Creates a new QR Code symbol based on the given existing object, but with a potentially
-	// different mask pattern. The version, error correction level, codewords, etc. of the newly
-	// created object are all identical to the argument object; only the mask may differ.
-	pub fn remask(qr: &QrCode, mask: Option<u8>) -> QrCode {
-		// Check arguments
-		assert!(mask == None || mask.unwrap() <= 7, "Mask out of range");
-		
-		// Copy fields
-		let mut result = QrCode {
-			version: qr.version,
-			size: qr.size,
-			mask: 0,  // Dummy value
-			errorcorrectionlevel: qr.errorcorrectionlevel,
-			modules: qr.modules.clone(),
-			isfunction: qr.isfunction.clone(),
-		};
-		
-		// Handle masking
-		result.apply_mask(qr.mask);  // Undo old mask
-		result.handle_constructor_masking(mask);
-		result
-	}
-	
-	
 	// Returns this QR Code's version, in the range [1, 40].
 	pub fn version(&self) -> u8 {
 		self.version