diff --git a/src/main/java/ch/fritteli/labyrinth/PDFRenderer.java b/src/main/java/ch/fritteli/labyrinth/PDFRenderer.java
index 1680ef5..e0474a0 100644
--- a/src/main/java/ch/fritteli/labyrinth/PDFRenderer.java
+++ b/src/main/java/ch/fritteli/labyrinth/PDFRenderer.java
@@ -1,6 +1,7 @@
 package ch.fritteli.labyrinth;
 
 import lombok.NonNull;
+import lombok.RequiredArgsConstructor;
 import lombok.Value;
 import org.apache.pdfbox.pdmodel.PDDocument;
 import org.apache.pdfbox.pdmodel.PDDocumentInformation;
@@ -26,63 +27,104 @@ public class PDFRenderer implements Renderer<byte[]> {
         return new PDFRenderer();
     }
 
-    private static boolean isValid(@NonNull final Position position) {
-        return position.getX() >= 0 && position.getY() >= 0;
-    }
-
     @Override
     @NonNull
     public byte[] render(@NonNull final Labyrinth labyrinth) {
-        final float pageWidth = labyrinth.getWidth() * SCALE + 2 * MARGIN;
-        final float pageHeight = labyrinth.getHeight() * SCALE + 2 * MARGIN;
-
-        final PDDocument pdDocument = new PDDocument();
-        final PDDocumentInformation info = new PDDocumentInformation();
-        info.setTitle("Labyrinth " + labyrinth.getWidth() + "x" + labyrinth.getHeight() + ", ID " + labyrinth.getRandomSeed());
-        pdDocument.setDocumentInformation(info);
-        final PDPage page = new PDPage(new PDRectangle(pageWidth, pageHeight));
-        final PDPage solution = new PDPage(new PDRectangle(pageWidth, pageHeight));
-        pdDocument.addPage(page);
-        pdDocument.addPage(solution);
-        try (final PDPageContentStream labyrinthPageContentStream = new PDPageContentStream(pdDocument, page);
-             final PDPageContentStream solutionPageContentStream = new PDPageContentStream(pdDocument, solution)) {
-            setUpPageContentStream(labyrinthPageContentStream);
-            setUpPageContentStream(solutionPageContentStream);
-            this.drawHorizonzalLines(labyrinth, labyrinthPageContentStream, solutionPageContentStream);
-            this.drawVerticalLines(labyrinth, labyrinthPageContentStream, solutionPageContentStream);
-            this.drawSolution(labyrinth, solutionPageContentStream);
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
-        final ByteArrayOutputStream output = new ByteArrayOutputStream();
-        try {
-            pdDocument.save(output);
-            pdDocument.close();
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
-        return output.toByteArray();
+        final Generator generator = new Generator(labyrinth);
+        return generator.generate();
     }
 
-    private void setUpPageContentStream(@NonNull final PDPageContentStream pageContentStream) throws IOException {
-        pageContentStream.setLineCapStyle(BasicStroke.CAP_ROUND);
-        pageContentStream.setLineJoinStyle(BasicStroke.JOIN_ROUND);
-        pageContentStream.setLineWidth(1.0f);
-        pageContentStream.setStrokingColor(Color.BLACK);
-        pageContentStream.setNonStrokingColor(Color.BLACK);
-    }
 
-    private void drawHorizonzalLines(@NonNull final Labyrinth labyrinth,
-                                     @NonNull final PDPageContentStream... contentStreams) throws IOException {
-        // PDF has the origin in the lower left corner. We want it in the upper left corner, hence some magic is required.
-        Coordinate coordinate = new Coordinate(0f, 0f);
-        for (int y = 0; y < labyrinth.getHeight(); y++) {
+    @RequiredArgsConstructor
+    private static class Generator {
+        @NonNull
+        private final Labyrinth labyrinth;
+
+        private static boolean isValid(@NonNull final Position position) {
+            return position.getX() >= 0 && position.getY() >= 0;
+        }
+
+        public byte[] generate() {
+            final float pageWidth = this.labyrinth.getWidth() * SCALE + 2 * MARGIN;
+            final float pageHeight = this.labyrinth.getHeight() * SCALE + 2 * MARGIN;
+
+            final PDDocument pdDocument = new PDDocument();
+            final PDDocumentInformation info = new PDDocumentInformation();
+            info.setTitle("Labyrinth " + this.labyrinth.getWidth() + "x" + this.labyrinth.getHeight() + ", ID " + this.labyrinth.getRandomSeed());
+            pdDocument.setDocumentInformation(info);
+            final PDPage page = new PDPage(new PDRectangle(pageWidth, pageHeight));
+            final PDPage solution = new PDPage(new PDRectangle(pageWidth, pageHeight));
+            pdDocument.addPage(page);
+            pdDocument.addPage(solution);
+            try (final PDPageContentStream labyrinthPageContentStream = new PDPageContentStream(pdDocument, page);
+                 final PDPageContentStream solutionPageContentStream = new PDPageContentStream(pdDocument, solution)) {
+                setUpPageContentStream(labyrinthPageContentStream);
+                setUpPageContentStream(solutionPageContentStream);
+                this.drawHorizonzalLines(labyrinthPageContentStream, solutionPageContentStream);
+                this.drawVerticalLines(labyrinthPageContentStream, solutionPageContentStream);
+                this.drawSolution(solutionPageContentStream);
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+            final ByteArrayOutputStream output = new ByteArrayOutputStream();
+            try {
+                pdDocument.save(output);
+                pdDocument.close();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+            return output.toByteArray();
+        }
+
+        private void setUpPageContentStream(@NonNull final PDPageContentStream pageContentStream) throws IOException {
+            pageContentStream.setLineCapStyle(BasicStroke.CAP_ROUND);
+            pageContentStream.setLineJoinStyle(BasicStroke.JOIN_ROUND);
+            pageContentStream.setLineWidth(1.0f);
+            pageContentStream.setStrokingColor(Color.BLACK);
+            pageContentStream.setNonStrokingColor(Color.BLACK);
+        }
+
+        private void drawHorizonzalLines(@NonNull final PDPageContentStream... contentStreams) throws IOException {
+            // PDF has the origin in the lower left corner. We want it in the upper left corner, hence some magic is required.
+            Coordinate coordinate = new Coordinate(0f, 0f);
+            for (int y = 0; y < this.labyrinth.getHeight(); y++) {
+                boolean isPainting = false;
+                coordinate = coordinate.withY(y);
+                for (int x = 0; x < this.labyrinth.getWidth(); x++) {
+                    final Tile currentTile = this.labyrinth.getTileAt(x, y);
+                    coordinate = coordinate.withX(x);
+                    if (currentTile.hasWallAt(Direction.TOP)) {
+                        if (!isPainting) {
+                            for (final PDPageContentStream contentStream : contentStreams) {
+                                contentStream.moveTo(coordinate.getX(), coordinate.getY());
+                            }
+                            isPainting = true;
+                        }
+                    } else {
+                        if (isPainting) {
+                            for (final PDPageContentStream contentStream : contentStreams) {
+                                contentStream.lineTo(coordinate.getX(), coordinate.getY());
+                                contentStream.stroke();
+                            }
+                            isPainting = false;
+                        }
+                    }
+                }
+                if (isPainting) {
+                    coordinate = coordinate.withX(this.labyrinth.getWidth());
+                    for (final PDPageContentStream contentStream : contentStreams) {
+                        contentStream.lineTo(coordinate.getX(), coordinate.getY());
+                        contentStream.stroke();
+                    }
+                }
+            }
             boolean isPainting = false;
-            coordinate = coordinate.withY(y, labyrinth);
-            for (int x = 0; x < labyrinth.getWidth(); x++) {
-                final Tile currentTile = labyrinth.getTileAt(x, y);
+            int y = this.labyrinth.getHeight();
+            coordinate = coordinate.withY(this.labyrinth.getHeight());
+            for (int x = 0; x < this.labyrinth.getWidth(); x++) {
+                final Tile currentTile = this.labyrinth.getTileAt(x, y - 1);
                 coordinate = coordinate.withX(x);
-                if (currentTile.hasWallAt(Direction.TOP)) {
+                if (currentTile.hasWallAt(Direction.BOTTOM)) {
                     if (!isPainting) {
                         for (final PDPageContentStream contentStream : contentStreams) {
                             contentStream.moveTo(coordinate.getX(), coordinate.getY());
@@ -100,57 +142,55 @@ public class PDFRenderer implements Renderer<byte[]> {
                 }
             }
             if (isPainting) {
-                coordinate = coordinate.withX(labyrinth.getWidth());
+                coordinate = coordinate.withX(this.labyrinth.getWidth());
                 for (final PDPageContentStream contentStream : contentStreams) {
                     contentStream.lineTo(coordinate.getX(), coordinate.getY());
                     contentStream.stroke();
                 }
             }
         }
-        boolean isPainting = false;
-        int y = labyrinth.getHeight();
-        coordinate = coordinate.withY(labyrinth.getHeight(), labyrinth);
-        for (int x = 0; x < labyrinth.getWidth(); x++) {
-            final Tile currentTile = labyrinth.getTileAt(x, y - 1);
-            coordinate = coordinate.withX(x);
-            if (currentTile.hasWallAt(Direction.BOTTOM)) {
-                if (!isPainting) {
-                    for (final PDPageContentStream contentStream : contentStreams) {
-                        contentStream.moveTo(coordinate.getX(), coordinate.getY());
+
+        private void drawVerticalLines(@NonNull final PDPageContentStream... contentStreams) throws IOException {
+            // PDF has the origin in the lower left corner. We want it in the upper left corner, hence some magic is required.
+            Coordinate coordinate = new Coordinate(0f, 0f);
+            for (int x = 0; x < this.labyrinth.getWidth(); x++) {
+                boolean isPainting = false;
+                coordinate = coordinate.withX(x);
+                for (int y = 0; y < this.labyrinth.getHeight(); y++) {
+                    final Tile currentTile = this.labyrinth.getTileAt(x, y);
+                    coordinate = coordinate.withY(y);
+                    if (currentTile.hasWallAt(Direction.LEFT)) {
+                        if (!isPainting) {
+                            for (final PDPageContentStream contentStream : contentStreams) {
+                                contentStream.moveTo(coordinate.getX(), coordinate.getY());
+                            }
+                            isPainting = true;
+                        }
+                    } else {
+                        if (isPainting) {
+                            for (final PDPageContentStream contentStream : contentStreams) {
+                                contentStream.lineTo(coordinate.getX(), coordinate.getY());
+                                contentStream.stroke();
+                            }
+                            isPainting = false;
+                        }
                     }
-                    isPainting = true;
                 }
-            } else {
                 if (isPainting) {
+                    coordinate = coordinate.withY(this.labyrinth.getHeight());
                     for (final PDPageContentStream contentStream : contentStreams) {
                         contentStream.lineTo(coordinate.getX(), coordinate.getY());
                         contentStream.stroke();
                     }
-                    isPainting = false;
                 }
             }
-        }
-        if (isPainting) {
-            coordinate = coordinate.withX(labyrinth.getWidth());
-            for (final PDPageContentStream contentStream : contentStreams) {
-                contentStream.lineTo(coordinate.getX(), coordinate.getY());
-                contentStream.stroke();
-            }
-        }
-    }
-
-    private void drawVerticalLines(@NonNull final Labyrinth labyrinth,
-                                   @NonNull final PDPageContentStream... contentStreams) throws IOException {
-        // PDF has the origin in the lower left corner. We want it in the upper left corner, hence some magic is required.
-        Coordinate coordinate = new Coordinate(0f, 0f);
-        final float labyrinthHeight = labyrinth.getHeight() * SCALE;
-        for (int x = 0; x < labyrinth.getWidth(); x++) {
             boolean isPainting = false;
-            coordinate = coordinate.withX(x);
-            for (int y = 0; y < labyrinth.getHeight(); y++) {
-                final Tile currentTile = labyrinth.getTileAt(x, y);
-                coordinate = coordinate.withY(y, labyrinth);
-                if (currentTile.hasWallAt(Direction.LEFT)) {
+            int x = this.labyrinth.getWidth();
+            coordinate = coordinate.withX(this.labyrinth.getWidth());
+            for (int y = 0; y < this.labyrinth.getHeight(); y++) {
+                final Tile currentTile = this.labyrinth.getTileAt(x - 1, y);
+                coordinate = coordinate.withY(y);
+                if (currentTile.hasWallAt(Direction.RIGHT)) {
                     if (!isPainting) {
                         for (final PDPageContentStream contentStream : contentStreams) {
                             contentStream.moveTo(coordinate.getX(), coordinate.getY());
@@ -168,138 +208,94 @@ public class PDFRenderer implements Renderer<byte[]> {
                 }
             }
             if (isPainting) {
-                coordinate = coordinate.withY(labyrinth.getHeight(), labyrinth);
+                coordinate = coordinate.withY(this.labyrinth.getHeight());
                 for (final PDPageContentStream contentStream : contentStreams) {
                     contentStream.lineTo(coordinate.getX(), coordinate.getY());
                     contentStream.stroke();
                 }
             }
         }
-        boolean isPainting = false;
-        int x = labyrinth.getWidth();
-        coordinate = coordinate.withX(labyrinth.getWidth());
-        for (int y = 0; y < labyrinth.getHeight(); y++) {
-            final Tile currentTile = labyrinth.getTileAt(x - 1, y);
-            coordinate = coordinate.withY(y, labyrinth);
-            if (currentTile.hasWallAt(Direction.RIGHT)) {
-                if (!isPainting) {
-                    for (final PDPageContentStream contentStream : contentStreams) {
-                        contentStream.moveTo(coordinate.getX(), coordinate.getY());
+
+        private void drawSolution(@NonNull final PDPageContentStream pageContentStream) throws IOException {
+            // Draw the solution in red
+            pageContentStream.setStrokingColor(Color.RED);
+            // PDF has the origin in the lower left corner. We want it in the upper left corner, hence some magic is required.
+            final Position end = this.labyrinth.getEnd();
+            Position currentPosition = this.labyrinth.getStart();
+            Position previousPosition = null;
+            SolutionCoordinate coordinate = new SolutionCoordinate(currentPosition.getX(), currentPosition.getY());
+            pageContentStream.moveTo(coordinate.getX(), coordinate.getY());
+            do {
+                Position newCurrent = this.findNextSolutionPosition(previousPosition, currentPosition);
+                previousPosition = currentPosition;
+                currentPosition = newCurrent;
+                coordinate = new SolutionCoordinate(currentPosition.getX(), currentPosition.getY());
+                pageContentStream.lineTo(coordinate.getX(), coordinate.getY());
+            } while (!currentPosition.equals(end));
+            pageContentStream.stroke();
+        }
+
+        @NonNull
+        private Position findNextSolutionPosition(@Nullable final Position previousPosition, @NonNull final Position currentPosition) {
+            final Tile currentTile = this.labyrinth.getTileAt(currentPosition);
+            for (final Direction direction : Direction.values()) {
+                if (!currentTile.hasWallAt(direction)) {
+                    final Position position = direction.translate(currentPosition);
+                    if (position.equals(previousPosition) || !isValid(position)) {
+                        continue;
                     }
-                    isPainting = true;
-                }
-            } else {
-                if (isPainting) {
-                    for (final PDPageContentStream contentStream : contentStreams) {
-                        contentStream.lineTo(coordinate.getX(), coordinate.getY());
-                        contentStream.stroke();
+                    if (this.labyrinth.getTileAt(position).isSolution()) {
+                        return position;
                     }
-                    isPainting = false;
                 }
             }
+            throw new IllegalStateException("We *SHOULD* never have gotten here. ... famous last words ...");
         }
-        if (isPainting) {
-            coordinate = coordinate.withY(labyrinth.getHeight(), labyrinth);
-            for (final PDPageContentStream contentStream : contentStreams) {
-                contentStream.lineTo(coordinate.getX(), coordinate.getY());
-                contentStream.stroke();
+
+        @Value
+        private class Coordinate {
+            float x;
+            float y;
+
+            public Coordinate(final float x, final float y) {
+                this.x = x;
+                this.y = y;
+            }
+
+            private float calcX(final int x) {
+                return x * SCALE + MARGIN;
+            }
+
+            private float calcY(final int y) {
+                return (Generator.this.labyrinth.getHeight() - y) * SCALE + MARGIN;
+            }
+
+            public Coordinate withX(final int x) {
+                return new Coordinate(calcX(x), this.y);
+            }
+
+            public Coordinate withY(final int y) {
+                return new Coordinate(this.x, calcY(y));
             }
         }
-    }
 
-    private void drawSolution(@NonNull final Labyrinth labyrinth,
-                              @NonNull final PDPageContentStream pageContentStream) throws IOException {
-        // Draw the solution in red
-        pageContentStream.setStrokingColor(Color.RED);
-        // PDF has the origin in the lower left corner. We want it in the upper left corner, hence some magic is required.
-        final Position end = labyrinth.getEnd();
-        Position currentPosition = labyrinth.getStart();
-        Position previousPosition = null;
-        SolutionCoordinate coordinate = new SolutionCoordinate(currentPosition.getX(), currentPosition.getY(), labyrinth);
-        pageContentStream.moveTo(coordinate.getX(), coordinate.getY());
-        do {
-            Position newCurrent = this.findNextSolutionPosition(labyrinth, previousPosition, currentPosition);
-            previousPosition = currentPosition;
-            currentPosition = newCurrent;
-            coordinate = new SolutionCoordinate(currentPosition.getX(), currentPosition.getY(), labyrinth);
-            pageContentStream.lineTo(coordinate.getX(), coordinate.getY());
-        } while (!currentPosition.equals(end));
-        pageContentStream.stroke();
-    }
+        @Value
+        private class SolutionCoordinate {
+            float x;
+            float y;
 
-    @NonNull
-    private Position findNextSolutionPosition(@NonNull final Labyrinth labyrinth, @Nullable final Position previousPosition, @NonNull final Position currentPosition) {
-        final Tile currentTile = labyrinth.getTileAt(currentPosition);
-        for (final Direction direction : Direction.values()) {
-            if (!currentTile.hasWallAt(direction)) {
-                final Position position = direction.translate(currentPosition);
-                if (position.equals(previousPosition) || !isValid(position)) {
-                    continue;
-                }
-                if (labyrinth.getTileAt(position).isSolution()) {
-                    return position;
-                }
+            public SolutionCoordinate(final int x, final int y) {
+                this.x = calcX(x);
+                this.y = calcY(y);
             }
-        }
-        throw new IllegalStateException("We *SHOULD* never have gotten here. ... famous last words ...");
-    }
 
-    @Value
-    private static class Coordinate {
-        float x;
-        float y;
+            private float calcX(final int x) {
+                return x * SCALE + SCALE / 2 + MARGIN;
+            }
 
-        public Coordinate(final float x, final float y) {
-            this.x = x;
-            this.y = y;
-        }
-
-        private static float calcX(final int x) {
-            return x * SCALE + MARGIN;
-        }
-
-        private static float calcY(final int y, @NonNull final Labyrinth labyrinth) {
-            return (labyrinth.getHeight() - y) * SCALE + MARGIN;
-        }
-
-        public Coordinate withX(final int x) {
-            return new Coordinate(calcX(x), this.y);
-        }
-
-        public Coordinate withY(final int y, @NonNull final Labyrinth labyrinth) {
-            return new Coordinate(this.x, calcY(y, labyrinth));
-        }
-    }
-
-    @Value
-    private static class SolutionCoordinate {
-        float x;
-        float y;
-
-        public SolutionCoordinate(final float x, final float y) {
-            this.x = x;
-            this.y = y;
-        }
-
-        public SolutionCoordinate(final int x, final int y, @NonNull final Labyrinth labyrinth) {
-            this.x = calcX(x);
-            this.y = calcY(y, labyrinth);
-        }
-
-        private static float calcX(final int x) {
-            return x * SCALE + SCALE / 2 + MARGIN;
-        }
-
-        private static float calcY(final int y, @NonNull final Labyrinth labyrinth) {
-            return (labyrinth.getHeight() - y) * SCALE - SCALE / 2 + MARGIN;
-        }
-
-        public SolutionCoordinate withX(final int x) {
-            return new SolutionCoordinate(calcX(x), this.y);
-        }
-
-        public SolutionCoordinate withY(final int y, @NonNull final Labyrinth labyrinth) {
-            return new SolutionCoordinate(this.x, calcY(y, labyrinth));
+            private float calcY(final int y) {
+                return (Generator.this.labyrinth.getHeight() - y) * SCALE - SCALE / 2 + MARGIN;
+            }
         }
     }
 }