In 44 patients with suspected dissecting aneurysm of the aorta, an aortographic diagnosis of dissection, based on the demonstration of a narrowed true lumen and of a false channel, was made in 23.

Dudeney’s original solution for transforming an equilateral triangle into a perfect square through dissection involves only four pieces, a solution that has now been proved to be the optimal solution.

In 1907, the English author and mathematician Henry Ernest Dudeney posed a puzzle: Can any equilateral triangle be cut into as few pieces as possible that will fit together to form a perfect square?