A math puzzle of many years has finally been solved - and this time even tilers can benefit from it. The unsolved mystery was:
How many pentagonal tiles can be used to completely cover a wall?
The answer: with 15 different pentagonal tiles.
The researcher Michael Rao from the French research centre CNRS came up with this solution.
In 1918, the German mathematician Karl Reinhardt showed that a wall can be completely covered with all triangular, square and hexagonal tiles. It is impossible to do this with square and polygonal tiles. But if he could handle pentagonal ones remained a mystery to him.