What fraction of these regular polygons is shaded red?
As a child, I remember working for a couple of weeks on a challenge set by my brother: In a snooker triangle there are 15 balls arranged in 5 rows. How many would there be in 100 rows? 25 years on, this is my response!
I was playing around with images to represent geometric series and was pleasantly surprised by the connections between these two.
Comparagrams 