diff --git a/c/qrcodegen.c b/c/qrcodegen.c
index 289b581..7ef34d0 100644
--- a/c/qrcodegen.c
+++ b/c/qrcodegen.c
@@ -359,15 +359,15 @@ static void drawWhiteFunctionModules(uint8_t qrcode[], int version) {
 	}
 	
 	// Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
-	for (int i = -4; i <= 4; i++) {
-		for (int j = -4; j <= 4; j++) {
-			int dist = abs(i);
-			if (abs(j) > dist)
-				dist = abs(j);
+	for (int dy = -4; dy <= 4; dy++) {
+		for (int dx = -4; dx <= 4; dx++) {
+			int dist = abs(dy);
+			if (abs(dx) > dist)
+				dist = abs(dx);
 			if (dist == 2 || dist == 4) {
-				setModuleBounded(qrcode, 3 + j, 3 + i, false);
-				setModuleBounded(qrcode, qrsize - 4 + j, 3 + i, false);
-				setModuleBounded(qrcode, 3 + j, qrsize - 4 + i, false);
+				setModuleBounded(qrcode, 3 + dx, 3 + dy, false);
+				setModuleBounded(qrcode, qrsize - 4 + dx, 3 + dy, false);
+				setModuleBounded(qrcode, 3 + dx, qrsize - 4 + dy, false);
 			}
 		}
 	}
@@ -379,9 +379,9 @@ static void drawWhiteFunctionModules(uint8_t qrcode[], int version) {
 		for (int j = 0; j < numAlign; j++) {
 			if ((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0))
 				continue;  // Don't draw on the three finder corners
-			for (int k = -1; k <= 1; k++) {
-				for (int l = -1; l <= 1; l++)
-					setModule(qrcode, alignPatPos[i] + l, alignPatPos[j] + k, k == 0 && l == 0);
+			for (int dy = -1; dy <= 1; dy++) {
+				for (int dx = -1; dx <= 1; dx++)
+					setModule(qrcode, alignPatPos[i] + dx, alignPatPos[j] + dy, dy == 0 && dx == 0);
 			}
 		}
 	}
diff --git a/cpp/QrCode.cpp b/cpp/QrCode.cpp
index 9c4db53..77faed7 100644
--- a/cpp/QrCode.cpp
+++ b/cpp/QrCode.cpp
@@ -270,10 +270,10 @@ void QrCode::drawVersion() {
 
 
 void QrCode::drawFinderPattern(int x, int y) {
-	for (int i = -4; i <= 4; i++) {
-		for (int j = -4; j <= 4; j++) {
-			int dist = std::max(std::abs(i), std::abs(j));  // Chebyshev/infinity norm
-			int xx = x + j, yy = y + i;
+	for (int dy = -4; dy <= 4; dy++) {
+		for (int dx = -4; dx <= 4; dx++) {
+			int dist = std::max(std::abs(dy), std::abs(dx));  // Chebyshev/infinity norm
+			int xx = x + dx, yy = y + dy;
 			if (0 <= xx && xx < size && 0 <= yy && yy < size)
 				setFunctionModule(xx, yy, dist != 2 && dist != 4);
 		}
@@ -282,9 +282,9 @@ void QrCode::drawFinderPattern(int x, int y) {
 
 
 void QrCode::drawAlignmentPattern(int x, int y) {
-	for (int i = -2; i <= 2; i++) {
-		for (int j = -2; j <= 2; j++)
-			setFunctionModule(x + j, y + i, std::max(std::abs(i), std::abs(j)) != 1);
+	for (int dy = -2; dy <= 2; dy++) {
+		for (int dx = -2; dx <= 2; dx++)
+			setFunctionModule(x + dx, y + dy, std::max(std::abs(dy), std::abs(dx)) != 1);
 	}
 }
 
diff --git a/java/io/nayuki/qrcodegen/QrCode.java b/java/io/nayuki/qrcodegen/QrCode.java
index 47b7195..ffc8a79 100644
--- a/java/io/nayuki/qrcodegen/QrCode.java
+++ b/java/io/nayuki/qrcodegen/QrCode.java
@@ -402,10 +402,10 @@ public final class QrCode {
 	// Draws a 9*9 finder pattern including the border separator,
 	// with the center module at (x, y). Modules can be out of bounds.
 	private void drawFinderPattern(int x, int y) {
-		for (int i = -4; i <= 4; i++) {
-			for (int j = -4; j <= 4; j++) {
-				int dist = Math.max(Math.abs(i), Math.abs(j));  // Chebyshev/infinity norm
-				int xx = x + j, yy = y + i;
+		for (int dy = -4; dy <= 4; dy++) {
+			for (int dx = -4; dx <= 4; dx++) {
+				int dist = Math.max(Math.abs(dy), Math.abs(dx));  // Chebyshev/infinity norm
+				int xx = x + dx, yy = y + dy;
 				if (0 <= xx && xx < size && 0 <= yy && yy < size)
 					setFunctionModule(xx, yy, dist != 2 && dist != 4);
 			}
@@ -416,9 +416,9 @@ public final class QrCode {
 	// Draws a 5*5 alignment pattern, with the center module
 	// at (x, y). All modules must be in bounds.
 	private void drawAlignmentPattern(int x, int y) {
-		for (int i = -2; i <= 2; i++) {
-			for (int j = -2; j <= 2; j++)
-				setFunctionModule(x + j, y + i, Math.max(Math.abs(i), Math.abs(j)) != 1);
+		for (int dy = -2; dy <= 2; dy++) {
+			for (int dx = -2; dx <= 2; dx++)
+				setFunctionModule(x + dx, y + dy, Math.max(Math.abs(dy), Math.abs(dx)) != 1);
 		}
 	}
 	
diff --git a/javascript/qrcodegen.js b/javascript/qrcodegen.js
index 1492733..63d489d 100644
--- a/javascript/qrcodegen.js
+++ b/javascript/qrcodegen.js
@@ -276,10 +276,10 @@ var qrcodegen = new function() {
 		// Draws a 9*9 finder pattern including the border separator,
 		// with the center module at (x, y). Modules can be out of bounds.
 		function drawFinderPattern(x, y) {
-			for (var i = -4; i <= 4; i++) {
-				for (var j = -4; j <= 4; j++) {
-					var dist = Math.max(Math.abs(i), Math.abs(j));  // Chebyshev/infinity norm
-					var xx = x + j, yy = y + i;
+			for (var dy = -4; dy <= 4; dy++) {
+				for (var dx = -4; dx <= 4; dx++) {
+					var dist = Math.max(Math.abs(dy), Math.abs(dx));  // Chebyshev/infinity norm
+					var xx = x + dx, yy = y + dy;
 					if (0 <= xx && xx < size && 0 <= yy && yy < size)
 						setFunctionModule(xx, yy, dist != 2 && dist != 4);
 				}
@@ -290,9 +290,9 @@ var qrcodegen = new function() {
 		// Draws a 5*5 alignment pattern, with the center module
 		// at (x, y). All modules must be in bounds.
 		function drawAlignmentPattern(x, y) {
-			for (var i = -2; i <= 2; i++) {
-				for (var j = -2; j <= 2; j++)
-					setFunctionModule(x + j, y + i, Math.max(Math.abs(i), Math.abs(j)) != 1);
+			for (var dy = -2; dy <= 2; dy++) {
+				for (var dx = -2; dx <= 2; dx++)
+					setFunctionModule(x + dx, y + dy, Math.max(Math.abs(dy), Math.abs(dx)) != 1);
 			}
 		}
 		
diff --git a/python/qrcodegen.py b/python/qrcodegen.py
index e1326b8..15d9f7e 100644
--- a/python/qrcodegen.py
+++ b/python/qrcodegen.py
@@ -322,20 +322,20 @@ class QrCode(object):
 	def _draw_finder_pattern(self, x, y):
 		"""Draws a 9*9 finder pattern including the border separator,
 		with the center module at (x, y). Modules can be out of bounds."""
-		for i in range(-4, 5):
-			for j in range(-4, 5):
-				xx, yy = x + j, y + i
+		for dy in range(-4, 5):
+			for dx in range(-4, 5):
+				xx, yy = x + dx, y + dy
 				if (0 <= xx < self._size) and (0 <= yy < self._size):
 					# Chebyshev/infinity norm
-					self._set_function_module(xx, yy, max(abs(i), abs(j)) not in (2, 4))
+					self._set_function_module(xx, yy, max(abs(dy), abs(dx)) not in (2, 4))
 	
 	
 	def _draw_alignment_pattern(self, x, y):
 		"""Draws a 5*5 alignment pattern, with the center module
 		at (x, y). All modules must be in bounds."""
-		for i in range(-2, 3):
-			for j in range(-2, 3):
-				self._set_function_module(x + j, y + i, max(abs(i), abs(j)) != 1)
+		for dy in range(-2, 3):
+			for dx in range(-2, 3):
+				self._set_function_module(x + dx, y + dy, max(abs(dy), abs(dx)) != 1)
 	
 	
 	def _set_function_module(self, x, y, isblack):
diff --git a/rust/src/lib.rs b/rust/src/lib.rs
index a37a533..3bbf56a 100644
--- a/rust/src/lib.rs
+++ b/rust/src/lib.rs
@@ -367,12 +367,12 @@ impl QrCode {
 	// Draws a 9*9 finder pattern including the border separator,
 	// with the center module at (x, y). Modules can be out of bounds.
 	fn draw_finder_pattern(&mut self, x: i32, y: i32) {
-		for i in -4 .. 5 {
-			for j in -4 .. 5 {
-				let xx: i32 = x + j;
-				let yy: i32 = y + i;
+		for dy in -4 .. 5 {
+			for dx in -4 .. 5 {
+				let xx: i32 = x + dx;
+				let yy: i32 = y + dy;
 				if 0 <= xx && xx < self.size && 0 <= yy && yy < self.size {
-					let dist: i32 = std::cmp::max(i.abs(), j.abs());  // Chebyshev/infinity norm
+					let dist: i32 = std::cmp::max(dy.abs(), dx.abs());  // Chebyshev/infinity norm
 					self.set_function_module(xx, yy, dist != 2 && dist != 4);
 				}
 			}
@@ -383,9 +383,9 @@ impl QrCode {
 	// Draws a 5*5 alignment pattern, with the center module
 	// at (x, y). All modules must be in bounds.
 	fn draw_alignment_pattern(&mut self, x: i32, y: i32) {
-		for i in -2 .. 3 {
-			for j in -2 .. 3 {
-				self.set_function_module(x + j, y + i, std::cmp::max(i.abs(), j.abs()) != 1);
+		for dy in -2 .. 3 {
+			for dx in -2 .. 3 {
+				self.set_function_module(x + dx, y + dy, std::cmp::max(dy.abs(), dx.abs()) != 1);
 			}
 		}
 	}
diff --git a/typescript/qrcodegen.ts b/typescript/qrcodegen.ts
index 420407d..7d20e7d 100644
--- a/typescript/qrcodegen.ts
+++ b/typescript/qrcodegen.ts
@@ -345,11 +345,11 @@ namespace qrcodegen {
 		// Draws a 9*9 finder pattern including the border separator,
 		// with the center module at (x, y). Modules can be out of bounds.
 		private drawFinderPattern(x: int, y: int): void {
-			for (let i = -4; i <= 4; i++) {
-				for (let j = -4; j <= 4; j++) {
-					let dist: int = Math.max(Math.abs(i), Math.abs(j));  // Chebyshev/infinity norm
-					let xx: int = x + j;
-					let yy: int = y + i;
+			for (let dy = -4; dy <= 4; dy++) {
+				for (let dx = -4; dx <= 4; dx++) {
+					let dist: int = Math.max(Math.abs(dy), Math.abs(dx));  // Chebyshev/infinity norm
+					let xx: int = x + dx;
+					let yy: int = y + dy;
 					if (0 <= xx && xx < this.size && 0 <= yy && yy < this.size)
 						this.setFunctionModule(xx, yy, dist != 2 && dist != 4);
 				}
@@ -360,9 +360,9 @@ namespace qrcodegen {
 		// Draws a 5*5 alignment pattern, with the center module
 		// at (x, y). All modules must be in bounds.
 		private drawAlignmentPattern(x: int, y: int): void {
-			for (let i = -2; i <= 2; i++) {
-				for (let j = -2; j <= 2; j++)
-					this.setFunctionModule(x + j, y + i, Math.max(Math.abs(i), Math.abs(j)) != 1);
+			for (let dy = -2; dy <= 2; dy++) {
+				for (let dx = -2; dx <= 2; dx++)
+					this.setFunctionModule(x + dx, y + dy, Math.max(Math.abs(dy), Math.abs(dx)) != 1);
 			}
 		}