Grids of Thermometers comes from Frozax Games. I reviewed this game about 4 years ago. It's been updated and is much better.
The object is to fill the grid with mercury (red). It's very logical, fun and addictive. Embergram (see link below) is very similar and very cool.
I've spent a lot of time on this game. One of the best features is the clock. Can you solve an 11 x 11 grid in 5 minutes?https://apps.apple.com/us/app/grids-of-thermometers/id1071003654