Math Finger Paintings

My final project in calculus class (2008). See as list.

$A fingerpainting of a rainbow, over the ocean on the left and a grassy hill on the right. The red end of the rainbow is labelled (in red) "low freq"; the blue end of the rainbow is labelled (in blue) "high freq". The ocean is represented by a simple wavy line, which is labelled "-|sin|".$
Rainbow!
Tesseract
Pascal's Triangle
Calculus