1 2 3
4 5 6
7 8 9
delete delete pencilnumbers toggle
full? rows valid? cols valid? check grid
delete pencilnumbers where big delete all pencilnumbers

Hotkeys:
1-9: Indsæt tal
Del: Slet indhold i markerede celle (sletter små tal hvis disse er aktive)
Space: Skift mellem store og små tal
Piletaster: