Greyscale figures [21-30]
 (Oscar Reutersvard) |
 (Oscar Reutersvard) |
 (Oscar Reutersvard) |
 (Oscar Reutersvard) |
 (Oscar Reutersvard) |
 (Oscar Reutersvard) |
 (Oscar Reutersvard) |
 |
 |
 (Roger Penrose) |