Hold anywhere to fold the sheet inward, release to spring it back. Each wall has mirrored notches above and below the crease. Fold just enough so they meet and the crane slips through. Under-fold and you hit the wall; over-fold and the paper crushes you.
It's one verb (hold/release), offline, no account. Perfects, combos, close calls, and a ghost line of your best score. Free with ads; optional one-time Remove Ads.
Built in Swift for iOS 17+. Happy to talk about the feel tuning (fold warp, crush warning, haptics) or anything that felt unfair.
App Store: https://apps.apple.com/us/app/paperflip/id6807705987 Site: https://abiaolhb.github.io/PaperFlipHtml/
Curious what tripped you up in the first 30 seconds.