Haisu ("House") is a logic puzzle invented by William Hu. A square or rectangular grid is divided into regions. The aim is to draw a line ("path") from S (start) to G (goal) that goes through all cells. The line cannot cross itself. The line can visit each region more than once. When the line passes over a cell with a big number N, it is on its Nth entry to the region. If a region has a small number n in the top left corner, the line must visit this region a total of n times.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.