     // Time varying pixel color
      vec3 col = 0.5 + 0.5*cos(iTime+uv.xyx+vec3(0,2,4));

      // Output to screen
      fragColor = vec4(col,1.0);
    }

    // -- End of Shadertoy code


    void main() {
      mainImage(gl_FragColor, gl_FragCoord.xy);
    }
  </script>
  <script>
    shaderWebBackground.shade({
      shaders: {
        Image: {
          uniforms: {
            iResolution: (gl, loc, ctx) => gl.uniform2f(loc, ctx.width, ctx.height),
            iTime:       (gl, loc) => gl.uniform1f(l