Reappearing Towers

Kasey has been on a block kick, and we often find her playing in her room with her blocks. Also, we are constantly finding block towers all over the place. Most of the time they are in high traffic areas and they are usually quickly knocked down, which makes her upset. I try to have her put the blocks away, before dinner, before we leave the house, and before bed. However, every time I turn around the block towers are back.