Primes

You can move tiles of a prime number(blue tiles) up and down, left and right.
If tiles you moved overlapped other tiles, the number is added.
After you moved a tile, tiles which are not prime numbers (red tiles) divide into as the same number of tiles as the smallest non-1 divisor.
ex.) "12" tile → 2 tiles of "6" tile
"15" tile → 3 tiles of "5" tile
When tiles overflow, the game is over.
The tile which you added a number to just now doesn't divide.
If no tiles divided after you moved a tile, "2" or "3" tiles may appear.

Make as large numbers as possible.