We've been studying some geometry lately.   My math child is never content to do anything just like the books says, and when he saw  his Saxon book had an activity sheet with geometric shapes he was running upstairs to get the tangram set from its dusty spot on the bookshelf.  (We haven't used them since last year at this time!)

What followed  was more than an hour of working through the cards in this set.   He methodically went through each one, until he had completed every single card.