Round About
Do these arrangements have symmetry? This was inspired by a photo of a tiling design.
http://mathhombre.tumblr.com/post/124512304004/round-about-do-these-arrangements-have-symmetry
The N determines the number of red rhombs at the center, and then the growth function determines how many more at each level.
Or you can just make interesting designs. Some cool stuff happens when you include N in your rule, like (N-1)*x.
More GeoGebra at bit.ly/mh-ggb