I think I had a different version of this same idea when I was younger (a yellow/orange plastic “book” with different plastic inserts for shape variation) and I remember spending hours creating patterns with different colors. I highly recommend purchasing this very affordable set, for yourself or for your favorite young person.
“hypotrochoid is the mathematical term for a line traced by a fixed point in a circle (your pen) which is rotated around the inside of a larger circle. these beautiful flowing curves have fascinated mathematicians for centuries. different points within the small circle produce wildly different patterns. a classic and absorbing drawing set, easy and fun to use. 11 piece set in a tin with instructions.”