How it works
Each puzzle gives a start state, a few gate keys and a target, and the numbered buttons switch between them. The bars are the chances of reading 0 and of reading 1, and you are done when the state matches the target, including the signs. A factor on the whole state, such as a minus or i, does not count as a difference, because no measurement can see one.
The first five use H, X and Z. Later puzzles bring in S, which multiplies the amplitude for |1⟩ by i, and Y. A phase of i does not change the bars, so the line under them says when the relative phase is +i or −i.
Par is the shortest solution, revealed after you have found a solution of your own. A solved puzzle gets a dot on its number, green at par and amber over it, and that record stays on your device. The grid you copy is a row of squares, one per gate you used, green inside par and amber for the extra gates, and it does not say which letters you pressed.
If you want the sum written out, the note The sign is what cancels does the double Hadamard by hand. The qubit page draws the same qubit as a sphere, for when a picture helps more than a pair of bars.