Rainbow!

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|".

Low Frequency/High Frequency are labeled for the rainbow; Function for the waves is -|sin| (negative absolute value of sine).