Get-21 Game 

It's a math logic game with simple rules. 

Sum 2 neighboring cells to get 21. The Cell will be cleared. The Score will increase. 

If the Sum is more than 21 the Cell will be blocked until you get 21. The value of the Cell will be decreased by 21. Each time, when you get 21 only one blocked cell will be released.

If the Sum is equal to 13 the Cell will be blocked forever. 

On each step a random value from 1 to 11 appears in a random cell.

You can choose different field sizes and color themes.

Dark theme is very tranquil and helps to relax.