This cat is like a gymnast on the parallel bars! It looks strange but is actually not that uncommon to see photographs on the internet of cats sleeping or resting in very odd places that look uncomfortable to us. Cats tend to like to sleep in places that are sometimes very different to what we would consider normal for us. The cat sleeping across clothes hangers in a wardrobe comes to mind for example. My cats like to sleep across computer cables on my bed. It looks uncomfortable but they have a different idea of what is comfortable.
One common denominator for cats sleeping is warmth. The other is smell. A comforting smell either of us or them or both makes the location attractive. The comfort zone.