diff -r 000000000000 -r 56477205fdb5 minesweeper/src/main/java/org/apidesign/demo/minesweeper/MinesModel.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/minesweeper/src/main/java/org/apidesign/demo/minesweeper/MinesModel.java	Fri Feb 07 14:47:07 2014 +0100
@@ -0,0 +1,126 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (C) 2013 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package org.apidesign.demo.minesweeper;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+import net.java.html.json.ComputedProperty;
+import net.java.html.json.Function;
+import net.java.html.json.Model;
+import net.java.html.json.ModelOperation;
+import net.java.html.json.Property;
+
+/** Model of the mine field.
+ */
+@Model(className = "Mines", properties = {
+    @Property(name = "state", type = MinesModel.GameState.class),
+    @Property(name = "rows", type = Row.class, array = true),
+})
+final class MinesModel {
+    enum GameState {
+        IN_PROGRESS, WON, LOST;
+    }
+    
+    @Model(className = "Row", properties = {
+        @Property(name = "columns", type = Square.class, array = true)
+    })
+    static class RowModel {
+    }
+
+    @Model(className = "Square", properties = {
+        @Property(name = "state", type = SquareType.class),
+        @Property(name = "mine", type = boolean.class)
+    })
+    static class SquareModel {
+        @ComputedProperty static String text(SquareType state) {
+            if (state == null) return " ";
+            switch (state) {
+                case MINE: return "B";
+                case UNKNOWN: return "?";
+                case N_0: return " ";
+            }
+            return "" + state.ordinal();
+        }
+    }
+    
+    enum SquareType {
+        N_0, N_1, N_2, N_3, N_4, N_5, N_6, N_7, N_8,
+        UNKNOWN, MINE
+    }
+    
+    @ModelOperation static void init(Mines model, int width, int height, int mines) {
+        List<Row> rows = new ArrayList<Row>(height);
+        for (int y = 0; y < height; y++) {
+            Square[] columns = new Square[width];
+            for (int x = 0; x < width; x++) {
+                columns[x] = new Square(SquareType.UNKNOWN, false);
+            }
+            rows.add(new Row(columns));
+        }
+        
+        Random r = new Random();
+        while (mines > 0) {
+            int x = r.nextInt(width);
+            int y = r.nextInt(height);
+            final Square s = rows.get(y).getColumns().get(x);
+            if (s.isMine()) {
+                continue;
+            }
+            s.setMine(true);
+            mines--;
+        }
+
+        model.setState(GameState.IN_PROGRESS);
+        model.getRows().clear();
+        model.getRows().addAll(rows);
+    }
+    
+    static void showAllBombs(Mines model) {
+        for (Row row : model.getRows()) {
+            for (Square square : row.getColumns()) {
+                if (square.isMine()) {
+                    square.setState(SquareType.MINE);
+                }
+            }
+        }
+    }
+    
+    @Function static void click(Mines model, Square data) {
+        if (model.getState() != GameState.IN_PROGRESS) {
+            return;
+        }
+        
+        switch (data.getState()) {
+            case UNKNOWN: 
+                if (data.isMine()) {
+                    showAllBombs(model);
+                    model.setState(GameState.LOST);
+                } else {
+                    data.setState(SquareType.N_0);
+                }
+            break;
+        }
+    }
+}