Path Tracing

2 Spheres with 100 samples:

3 spheres with 256 samples:

4 spheres and 2 triangles with 256 samples. The triangles and the yellow sphere reflects green color.

4 spheres with 2 triangles. The white sphere reflects the blue color of the sphere above. The yellow sphere reflects the green of the sphere below. The light is on the left side. This time the image was rendered with 625 samples.