Daily Logic
Today's rack of 4×4 logic grids, drawn on a phosphor tube. Every row, column and 2×2 box holds 1 to 4 exactly once.
Amber numerals are the givens and cannot move. Tap a cell to cycle it 1→2→3→4→blank; keys 1-4 set it outright.
A clash flashes warm red and breaks your streak. Faint corner ticks note which digits a cell can still legally take.
Solve fast: a quick grid pays a large bonus and refills the tube. Drag or arrows scrub the cursor.
tap anywhere to strike the tube