support level 0
Play Soduko like in the real world (paperlike, no support)
support level 1
Definitely wrong symbols will be colored red
support level 2
Shows the number of possible symbols in all cells
support level 3
Shows all possibles symbols in the memo table, the number of
possible symbols can be blinded out
support level 4
Now you're able to solve the game by your computer. It enables the
solver.