, 21,   // middle rung top
     9, 11, 21,   21, 11, 23,   // middle rung right
    10, 22, 11,   22, 23, 11,   // middle rung bottom
    10,  3, 22,   22,  3, 15,   // stem right
     2, 14,  3,   14, 15,  3,   // bottom
     0, 12,  2,   12, 14,  2,   // left
  ];

  const quadColors = [
      200,  70, 120,  // left column front
      200,  70, 120,  // top rung front
      200,  70, 120,  // middle rung front

       80,  70, 200,  // left column back
       80,  70, 200,  // top rung back
       80,  7