a hole in the ocean

ok, it’s really on the shore, but it’s pretty darn close to have water pouring into it all ’round!


apparent motion


from the comments on the facebook post, some people couldn’t see the apparent motion in this figure and some people could start and stop the apparent motion.  once i read that, i learned that i could stop the motion, too, but then it got harder to start it back up… what’s YOUR experience?  anyone know why i checked “math” as one of the categories?