.position && opts.position.y) || 0) +
                        parseFloat(opts.height);
          var offsetZ = 0;

          var position = {
            x: offsetX,
            y: offsetY,
            z: offsetZ
          };

          for (var i = 1; i < numCubes; i++) {
            var newCubeOpts = Object.assign({}, opts);
            newCubeOpts.position = position;
            newCubeOpts.mixin = 'layer-' + (i + 1) + '--light';

            var newCube = createCube(newCubeOpts);
            parentCube