Creating complex surfaces with the folded grid, using the simple V-Pleat.
As interesting as they look, the following took about two hours to collapse.
complex v pleat with reference to 4.7_2 of Folding Techniques for Designers, tracing paper
Dividing the square sheet diagonally into 32 and horizontally into 16.
complex v pleat with reference to 4.5 of Folding Techniques for Designers, duplicating paper