They are a toy! You can fit them together to make a series of tubes, caps, and twists and turns to make a sort of grand 'habitrail' (such as are done for hamsters) for your pets! I designate a spot in my house yard, courtyard, or in a room to build these elaborate mazes and put my pets in various places around it to look like they are playing in the maze. They can't actually go in the tubes, but that's ok. It is all a game of pretend, and I like to pretend that I have happily spoiled pets indeed!