Slicing a Bagel

Get a bagel and a knife, then cut the bagel in two pieces which end up linked to each other.

The solution is presented HERE.

George William Hart (1955) is an American geometer who expresses himself both artistically and academically. He is also an interdepartmental research professor at the State University of New York in Stony Brook, New York. His artistic work includes sculpture, computer images, toys (e.g. Zome) and puzzles. His sculptures have been featured in articles in The New York Times, Science News, and other publications around the world.