The first has no arms. The second no legs, and the third has no body, just a head.
They all line up, the whistle blows and “splash” they are all in the pool.
The person who has no arms takes the lead instantly, but the one who has no legs is pulling for all they are worth and closing fast. The head, as you might have expected, just sank straight to the bottom of the pool.
Ten lengths later and the person who has no legs finishes first.
They can still see bubbles coming from the bottom of the pool, and so decide they had better dive down to rescue the one with just a head.
So, they pick up the head, swim back up to the surface and place it at the side of the pool, where-upon the head starts coughing and spluttering.
Eventually the head catches it’s breath and shouts: “Three long years I’ve spent learning to swim with my ears. Three long years! Then what do you know! Two minutes before the whistle, some wise guy puts a swimming cap on me!”
Image used under a Collective Commons License from https://www.pexels.com/photo/man-wearing-yellow-swimming-cap-about-to-swim-2062697/