  // create 2 vertex buffers
  const staticUnitSize =
    4;     // color is 4 bytes
  const changingUnitSize =
    2 * 4 + // offset is 2 32bit floats (4bytes each)
    2 * 4;  // scale is 2 32bit floats (4bytes each)
  const staticVertexBufferSize = staticUnitSize * kNumObjects;
  const changingVertexBufferSize = changingUnitSize * kNumObjects;

  const staticVertexBuffer = device.createBuffer({
    label: 'static vertex for objects',
    size: staticVertexBufferSize,
    usage: GPUBufferUsage.VERTEX | GP