Inside each sphere is a winding track and a small spherical ball. The goal is to get the spherical ball from the start to the finish without falling off the track. It is very addicting! The sphere on the left is easier than the sphere on the right, but by no means does this mean either are easy. I've maybe gotten 1/5 of the way through the blue and white sphere on the right. It's very difficult! As for the colored sphere on the left, I have finished it...once! That's it! This is the most addicting one because I feel I should be able to complete the maze. When I fail, I feel I have to try again because I know I'll get it the next time. But then I fail the next time, and the next time, and the next time!
These are fun to play around with and great gift ideas for kids (and adults)!