ertexColorFragmentShader], ["position", "vecRandom"]);
    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Shader and buffer setup successfully");

    var indices = new Uint32Array([0, 1, 2, 0, 2, 3]);
    var elements = gl.createBuffer();
    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, elements);
    gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, drawType);

    gl.clearColor(0.0, 0.0, 1.0, 1.0);  // Start with blue to indicate no pixels touched.
    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);



    gl.drawEl