Magnetic bottle cap tree!

thingiverse

You don't necessarily have to water a tree to see it grow. Bottle caps are enough. The tree is great for decoration but also for party games, and in the best case, you never have to pick up crown caps from the ground again! Everyone wants to see how the tree grows and will either throw their bottle caps onto the tree or carefully place them on it to ensure that none fall down. It can hold more than 32 bottle caps, but unfortunately I didn't have more to test it with.