For over a century, a simple yet tricky math problem had continued to baffle experts. Mathematicians struggled to find the fewest number of pieces needed to cut an equilateral triangle and rearrange ...

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?

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.