* Math.random();

        renderer.uniforms.u_color = [
          Math.random(),
          Math.random(),
          Math.random(),
          1];

        const {positions, cells} = randomShape(x, y, 3 + Math.floor(4 * Math.random()), rotation);
        renderer.setMeshData([{
          positions,
          cells,
        }]);

        renderer._draw();
      }
      requestAnimationFrame(render);
    }

    render();
  </script>
</body>
</html>