Everyone knows (?) "Squirrel" game.

Touching two or more side by side tiles disappears.
When it disappears, the tile falls down.
It fills the left when all the vertical is gone.
Clear all if you clear it.

A simple rule that does not get tired.
It is a killing time game that can face your inner face.

This game, the first time I did it was around the early 1990s.
I connected AIWA 's modem to EPSON PC - 486GF that I bought and dropped it from the grassroots BBS and played.
At that time, I felt like I had cleared quite easily, but it is quite difficult to do now.
I wonder if my head got stiff. I think that it will become gymnastics of the head.