diff --git a/test/public/tests.js b/test/public/tests.js
index 033119e..fe7ff13 100644
--- a/test/public/tests.js
+++ b/test/public/tests.js
@@ -13,6 +13,72 @@ tests['strokeRect()'] = function(ctx){
   ctx.strokeRect(50,50,50,50);
 };
 
+tests['fillRect()'] = function(ctx){
+  
+  function render(level){
+    ctx.fillStyle = getPointColour(122,122);
+    ctx.fillRect(0,0,240,240);
+    renderLevel(level,81,0);
+  }
+
+  function renderLevel(minimumLevel,level,y){
+    for (var x=0; x < 243 / level; ++x) {
+      drawBlock(x,y,level);
+    }
+    for (var x=0; x < 243 / level; x+=3){
+      drawBlock(x,y+1,level);
+      drawBlock(x+2,y+1,level);
+    }
+    for (var x=0; x < 243 / level; ++x){
+      drawBlock(x,y+2,level);
+    }
+    if ((y += 3) >= 243 / level){
+      y=0;
+      level /= 3;
+    }
+    if (level >= minimumLevel){
+      renderLevel(minimumLevel, level, y);
+    }
+  }
+
+  function drawBlock(x,y,level){
+    ctx.fillStyle = getPointColour(
+        x * level + (level-1) / 2
+      , y * level + (level-1) / 2);
+
+    ctx.fillRect(
+        x * level
+      , y * level
+      , level
+      , level
+      );
+  }
+
+  function getPointColour(x,y){
+    x= x / 121.5 - 1;
+    y= -y / 121.5 + 1;
+    var x2y2 = x * x + y * y;
+    if (x2y2 > 1){
+      return '#000';
+    } else {
+      var root = Math.sqrt(1 - x2y2);
+      var x3d = x * 0.7071067812 + root / 2 - y / 2;
+      var y3d = x * 0.7071067812 - root / 2 + y / 2;
+      var z3d = 0.7071067812 * root + 0.7071067812 * y;
+      var brightness= -x / 2 + root * 0.7071067812 + y / 2;
+      if (brightness < 0) brightness = 0;
+      return ''
+        + 'rgb(' + Math.round(brightness * 127.5 * (1 - y3d))
+        + ',' + Math.round(brightness * 127.5 * (x3d + 1))
+        + ',' + Math.round(brightness * 127.5 * (z3d + 1))
+        + ')'
+        ;
+   }
+  }
+
+  render(1);
+};
+
 tests['lineTo()'] = function(ctx){
   // Filled triangle
   ctx.beginPath();