Unlike the previous image and the Titchener Circles, the below image is 3-dimensional. Whiles the spheres may be the same size in a copy-and-paste sort of manner, the additional dimension really helps the farther sphere seem bigger and not just look bigger. The basic principles of Ebbinghaus illusion is there, the closer walls make the farther sphere look larger than the closer sphere where the walls are farther away. However, the way the walls are given depth and dimensional, it makes the audience think they are the same width all the way through. Because of that, and because our minds are used to recognizing things farther away as being bigger than they actually look, the farther sphere seems to dwarf the closer one.