gshisen.app - 1.3.0-2+b1 main

The object of the game is to remove all tiles from the field. Only
two matching tiles can be removed at a time. Two tiles can only be
removed if they can be connected with at most three connected lines.
Lines can be horizontal or vertical but not diagonal. Remember that
lines may cross the empty border. If you are stuck, you can use the
Hint feature to find two tiles which may be removed.