Proposed by Helmut Simonis
The perfect square placement problem (also called the squared square problem) is to pack a set of squares with given integer sizes into a bigger square in such a way that no squares overlap each other and all square borders are parallel to the border of the big square. For a perfect placement problem, all squares have different sizes. The sum of the square surfaces is equal to the surface of the packing square, so that there is no spare capacity. A simple perfect square placement problem is a perfect square placement problem in which no subset of the squares (greater than one) are placed in a rectangle.
A note with an example solution is available in the Data files section.