This is a simple, classic memory game based on the card game from the 1960s.
You can choose number of columns (even numbers only up to 12) and number of rows (1-9).
Click on two cards, and then click a third time. If the cards match, they disappear. If they don't match, they turn over, but now you know what they are.
When the game is over, a "game over" screen appears with the number of tries on it. And you get a shower of confetti.
It's open source. The game needs modifications, which can be found here in CONTRIBUTING.md.