diff --git a/src/sj/AbstractGame.d b/src/sj/AbstractGame.d
index eec5ff1..58ce4dd 100644
--- a/src/sj/AbstractGame.d
+++ b/src/sj/AbstractGame.d
@@ -23,7 +23,7 @@ class AbstractGame {
   }
   ///
   void Draw() {
-    gl.Clear(GL_COLOR_BUFFER_BIT);
+    gl.Clear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     scene_.Draw();
   }
 
diff --git a/src/sj/CubeProgram.d b/src/sj/CubeProgram.d
new file mode 100644
index 0000000..56d79a1
--- /dev/null
+++ b/src/sj/CubeProgram.d
@@ -0,0 +1,194 @@
+/// License: MIT
+module sj.CubeProgram;
+
+import std.conv,
+       std.range.primitives;
+
+import gl4d;
+
+///
+class CubeProgram {
+ public:
+  ///
+  alias Instance = mat4;
+
+  ///
+  enum ShaderHeader = "#version 330 core
+#extension GL_ARB_explicit_uniform_location : enable";
+
+  ///
+  enum VertexShaderSrc = ShaderHeader ~ q{
+    layout(location = 0) in vec3 vert;
+    layout(location = 1) in vec3 normal;
+
+    layout(location = 2) in vec4 m1;
+    layout(location = 3) in vec4 m2;
+    layout(location = 4) in vec4 m3;
+    layout(location = 5) in vec4 m4;
+
+    out vec3 normal_;
+
+    void main() {
+      mat4 m = transpose(mat4(m1, m2, m3, m4));
+
+      normal_     = (m * vec4(normal, 1)).xyz;
+      gl_Position = m * vec4(vert, 1);
+    }
+  };
+  ///
+  enum FragmentShaderSrc = ShaderHeader ~ q{
+    layout(location = 0) uniform vec3 light_color;
+    layout(location = 1) uniform vec3 light_direction;
+    layout(location = 2) uniform vec3 ambient_color;
+
+    in vec3 normal_;
+
+    out vec4 pixel_;
+
+    void main() {
+      float light = dot(normalize(light_direction), normalize(normal_));
+      vec3  color = clamp(light_color * light + ambient_color, 0, 1);
+
+      pixel_ = vec4(color, 1);
+    }
+  };
+
+  ///
+  enum MaxInstanceCount = 10;
+
+  ///
+  this() {
+    ProgramLinker linker;
+    linker.vertex   = VertexShader.Compile(VertexShaderSrc);
+    linker.fragment = FragmentShader.Compile(FragmentShaderSrc);
+    program_ = linker.Link();
+    program_.Validate();
+
+    vao_       = VertexArray.Create();
+    verts_     = ArrayBuffer.Create();
+    instances_ = ArrayBuffer.Create();
+
+    vao_.Bind();
+    VertexArrayAttacher attacher;
+    with (attacher) {
+      index     = 0;
+      type      = GL_FLOAT;
+      offset    = vec3.sizeof * 0;
+      stride    = vec3.sizeof * 2;
+      dimension = 3;
+      Attach(vao_, verts_);
+
+      index     = 1;
+      type      = GL_FLOAT;
+      offset    = vec3.sizeof * 1;
+      stride    = vec3.sizeof * 2;
+      dimension = 3;
+      Attach(vao_, verts_);
+
+      index     = 2;
+      type      = GL_FLOAT;
+      offset    = vec4.sizeof * 0;
+      stride    = vec4.sizeof * 4;
+      dimension = 4;
+      divisor   = 1;
+      Attach(vao_, instances_);
+      index   = 3;
+      offset += vec4.sizeof;
+      Attach(vao_, instances_);
+      index   = 4;
+      offset += vec4.sizeof;
+      Attach(vao_, instances_);
+      index   = 5;
+      offset += vec4.sizeof;
+      Attach(vao_, instances_);
+    }
+
+    verts_.Bind();
+    ArrayBufferAllocator verts_allocator;
+    with (verts_allocator) {
+      enum v = [
+        // left
+        vec3(-1, 1, -1), vec3(-1,  1,  1), vec3(-1, -1, 1),
+        vec3(-1, 1, -1), vec3(-1, -1, -1), vec3(-1, -1, 1),
+
+        // right
+        vec3(1, 1, -1), vec3(1,  1,  1), vec3(1, -1, 1),
+        vec3(1, 1, -1), vec3(1, -1, -1), vec3(1, -1, 1),
+
+        // top
+        vec3(-1, 1, -1), vec3(-1, 1,  1), vec3(1, 1, 1),
+        vec3(-1, 1, -1), vec3( 1, 1, -1), vec3(1, 1, 1),
+
+        // bottom
+        vec3(-1, -1, -1), vec3(-1, -1,  1), vec3(1, -1, 1),
+        vec3(-1, -1, -1), vec3( 1, -1, -1), vec3(1, -1, 1),
+
+        // front
+        vec3(-1, 1, -1), vec3( 1,  1, -1), vec3(1, -1, -1),
+        vec3(-1, 1, -1), vec3(-1, -1, -1), vec3(1, -1, -1),
+
+        // back
+        vec3(-1, 1, 1), vec3( 1,  1, 1), vec3(1, -1, 1),
+        vec3(-1, 1, 1), vec3(-1, -1, 1), vec3(1, -1, 1),
+      ];
+      enum n = [
+        vec3(-1,  0,  0),  // left
+        vec3( 1,  0,  0),  // right
+        vec3( 0,  1,  0),  // top
+        vec3( 0, -1,  0),  // bottom
+        vec3( 0,  0, -1),  // front
+        vec3( 0,  0,  1),  // back
+      ];
+      enum d = {
+        vec3[] d;
+        foreach (i, p; v) d ~= [p, n[i/6]];
+        return d;
+      }();
+
+      const d_mem = d;
+      data  = d_mem.ptr;
+      size  = d_mem[0].sizeof * d_mem.length;
+      usage = GL_STATIC_DRAW;
+      Allocate(verts_);
+    }
+
+    instances_.Bind();
+    ArrayBufferAllocator instances_allocator;
+    with (instances_allocator) {
+      data  = null;
+      size  = MaxInstanceCount * Instance.sizeof;
+      usage = GL_DYNAMIC_DRAW;
+      Allocate(instances_);
+    }
+  }
+
+  ///
+  void Draw(R)(R cubes, vec3 lcolor, vec3 light, vec3 acolor)
+      if (isInputRange!R && is(ElementType!R == Instance)) {
+    size_t length;
+    {
+      auto ptr = instances_.MapToWrite!Instance();
+      foreach (const ref c; cubes) {
+        assert(length < MaxInstanceCount);
+        ptr[length++] = c;
+      }
+    }
+
+    program_.Use();
+    program_.uniform!0 = lcolor;
+    program_.uniform!1 = light;
+    program_.uniform!2 = acolor;
+
+    vao_.Bind();
+    gl.DrawArraysInstanced(GL_TRIANGLES, 0, 6*6, length.to!int);
+  }
+
+ private:
+  ProgramRef program_;
+
+  VertexArrayRef vao_;
+
+  ArrayBufferRef verts_;
+
+  ArrayBufferRef instances_;
+}
diff --git a/src/sj/LobbyWorld.d b/src/sj/LobbyWorld.d
index 6dfddbc..922a580 100644
--- a/src/sj/LobbyWorld.d
+++ b/src/sj/LobbyWorld.d
@@ -1,21 +1,38 @@
 /// License: MIT
 module sj.LobbyWorld;
 
+import std.algorithm;
+
+import gl4d;
+
 import sjplayer.Background;
 
-import sj.ProgramSet;
+import sj.CubeProgram,
+       sj.ProgramSet;
 
 ///
 class LobbyWorld {
  public:
+  ///
+  enum Perspective = mat4.perspective(-0.5, 0.5, -0.5, 0.5, 0.1, 100);
+
   ///
   this(ProgramSet programs) {
-    background_ = new Background(programs.forPlayers.Get!BackgroundProgram);
+    background_ = new Background(programs.Get!BackgroundProgram);
+    cube_       = programs.Get!CubeProgram;
   }
 
   ///
   void Draw() {
+    gl.Disable(GL_DEPTH_TEST);
+    gl.DepthMask(false);
     background_.Draw();
+
+    gl.Enable(GL_DEPTH_TEST);
+    gl.DepthMask(true);
+    cube_.Draw(
+        cubes.map!(x => Perspective * view * x),
+        light_color, light_direction, ambient_color);
   }
 
   ///
@@ -23,6 +40,19 @@ class LobbyWorld {
     return background_;
   }
 
+  ///
+  mat4[] cubes;
+  ///
+  mat4 view = mat4.look_at(vec3(0, 0, -1), vec3(0, 0, 0), vec3(0, 1, 0));
+  ///
+  vec3 light_color = vec3(1, 1, 1, 1);
+  ///
+  vec3 light_direction = vec3(0, 1, 0);
+  ///
+  vec3 ambient_color = vec3(0.1, 0.1, 0.1);
+
  private:
   Background background_;
+
+  CubeProgram cube_;
 }
diff --git a/src/sj/ProgramSet.d b/src/sj/ProgramSet.d
index 97cae71..cb391ad 100644
--- a/src/sj/ProgramSet.d
+++ b/src/sj/ProgramSet.d
@@ -1,24 +1,46 @@
 /// License: MIT
 module sj.ProgramSet;
 
+import std.meta,
+       std.typecons;
+
 static import sjplayer = sjplayer.ProgramSet;
 
+import sj.CubeProgram;
+
 ///
 class ProgramSet {
  public:
+  alias Programs = Tuple!(
+      CubeProgram,
+    );
+
   ///
   this() {
-    for_players_ = new sjplayer.ProgramSet;
+    for_player_ = new sjplayer.ProgramSet;
+    foreach (ref p; programs_) {
+      p = new typeof(p);
+    }
   }
   ~this() {
-    for_players_.destroy();
+    for_player_.destroy();
+    foreach (p; programs_) {
+      p.destroy();
+    }
   }
 
   ///
-  @property sjplayer.ProgramSet forPlayers() {
-    return for_players_;
+  T Get(T)() {
+    enum index = staticIndexOf!(T, Programs.Types);
+    static if (index >= 0) {
+      return programs_[index];
+    } else {
+      return for_player_.Get!T;
+    }
   }
 
  private:
-  sjplayer.ProgramSet for_players_;
+  sjplayer.ProgramSet for_player_;
+
+  Programs programs_;
 }