It's not The Witness, but it is a puzzler by a talented indie developer. 1Button, known for games like Nekosan [Free], Mr Jump [Free], have created Trilogic [$1.99] as a followup to Bicolor [$1.99], their puzzler from 2014. Naturally, the big new element in this game? Instead of having two colors in a puzzle to contend with, now there are three different elements in a puzzle to play with. With a bit of Minesweeper influence, icons will show how many of that element you can drag from that spot into the board. The elements play a role, too: leaf drinks water, fire burns leaf, and water puts out fire. This order is key to solving the puzzles.

This is another neat little puzzler from 1Button that is easy to play, but will quickly prove to be quite challenging. It's $1.99, and has 180 levels, and the only IAP is for skipping levels if you get stuck. 1Button has a great track record, and the idea seems quite clever from what I've played, so give it a shot if it interests you.