Get 3 gems in a row.
Some mindless engagement.
A grid shows various gem shapes. Use the D-pad to select a gem and swap it with the gem next to it, so you can line up 3 gems of the same shape in a row. Try to get as many rows as you can within the time limit.
You can pick up how to play the game almost instantly.
Because the game is so simple, it can feel boring after a while.