Here’s a slightly updated version of a card game I made in 2014. It was originally targeted at the iPad, but for the purposes of this post I’ve altered it to work on any size screen.
Essentially it’s a card matching game. Find two matching cards that have an edge or corner touching each other, click them both, and one is removed.
Each time you remove a card (and score a point) the remaining cards are shuffled along to fill in the gap. This creates new opportunities for new matches.
To understand how the matching rules work you can turn on "cheat mode" to see all the matches that exist at that point (Figure 1).
In Figure 2 you can see me finding pairs of cards and clicking on them. When I click a touching pair, one of them is removed and I score a point.
If you need to swap a couple of cards around to make better matches, you can (they don’t need to be next to each as shown in Figure 3, they can be any two cards). The "swap mode" button gives you just three chances to do that, though, so use each one wisely.
Scroll down to try playing the game. It’s simple to get started and you’ll soon figure out some strategies to improve your scores (I think my best is around 33).
Eventually I’d like to post this as a standalone game at its own domain, but that’s for another day. The code needs a thorough overhaul first.