Hexagonal Tetris
The ICFP 2015 Contest required contestants to play a tetris-like game on a hexagonal grid, to maximise their scores over various problems. Various shapes appear at the top of a playing area, and need to be tightly packed together. Once a horizontal line is fully packed, the whole line disappears, making way for more shapes to be packed in. In addition, special "movement combos" known as "power phrases" could be invoked to gain additional points. The following are some examples from the contest, and their solutions.