Orbital Quartet

Orbit Five: Linked pairs total five, while fewer fixed digits make those sum clues useful. Bond badges identify the paired cells.

Select a blank, then a digit. Fill every row, column and lettered region without repeats. Pencil marks support deduction; Check evaluates constraints.

Tap or click the controls. Keyboard: Tab and Enter/Space operate every button; arrows/WASD move where available, R restarts, Z undoes calm puzzles.

Mistakes remain revisable. Unlimited undo and restart recover deadlocks.