Everyone else celebrates Valentine's Day today; my son and I celebrate Family Day. I adopted my son 8 years ago today; it was pretty exciting to finally become a mama (at 46) on Valentine's Day.
Check out these mathematical Valentines. I won't have time today to recreate the one I made years ago on an early HP computer with a plotter, but it used trig functions, and zigzagged up and down from one point to the next (odd-numbered points were something like 10% bigger than even-numbered points) for a somewhat lacy effect. You could do that in Scratch, I bet.
Maybe I'll get to edit this all day. Here's David Cox with Geogebra. And here's Vi Hart with Mobius Hearts.