Keyboard arrows ← ↑ → ↓ to move between the cells in the four directions.
Tab key ⇥ to move to the next definition.
Spacebar to change the direction of the selected word.
Backspace key to delete the value of the cell e move to the previous one.
Delete key to delete the value of the cell without moving.
Click on a definition to go to the respective cells.
Click on "check" to check with the solution.