settings

pencil sounds

quiet paper & pencil scratch feedback

tactile haptics

subtle vibrations on mobile devices

auto-remove pencil notes

erase candidate notes when confirmed digit is placed

highlight matching numbers

subtly illuminate other cells with the same number

highlight related row & block

tint the active row, column, and 3x3 block

show timer

display elapsed time above the board

show mistakes counter

track incorrect entries during puzzle solving