How to play
One column. One sum.
Turn the concentric rings until the numbers in every column, one number from each ring, add up to the target in the centre. Do not add numbers next to each other along a ring. All columns must be correct at the same time.
Turn with your fingertips
Drag any ring clockwise or anticlockwise. It snaps to the next segment when you let go. You can also choose a ring in the select menu, then tap an arrow. The outermost ring is number 1. Keyboard: select a ring with Tab, then use Left or Right.
A light for every column
Each column has two LEDs: one in the centre and one on the outer rim. Both are red with a minus sign while its sum is incorrect, and green with a check mark when it matches the target. The small arrow buttons below select a column and show its addition clearly.
Your combination
Set 3, 4 or 5 rings, 4–16 columns, and any whole target number from 30 to 100 independently. Every new puzzle has a solution. Changing these three settings starts a new puzzle after confirmation. Timer display and reduced motion do not change the puzzle.
A little assistance
Moves one ring one step toward a valid solution. Each use is counted.