gazellecheetah/gum-gum-hand-stretch — reverse-engineered prompt

Build me a little webcam app where I can pinch my thumb and fingertip together and then drag my hand to create a stretchy cartoon arm effect, like Luffy’s gum gum move. I want it to freeze an anchor point when the pinch starts, stretch a rubbery tube from that point to my live hand position while I move, and then snap back with a slightly bouncy elastic feel when I let go.

It should feel stable and not flicker if my fingers are close together, and the stretch should look smooth and organic, not just a straight line. If possible, make the arm taper and keep a rounded shiny look while it stretches.

Please include a live webcam mode, plus a simple self test mode that runs without the camera. I’d also like a few keyboard toggles for things like mirror mode, a debug overlay, using any finger for the pinch, and an alternate face cheek anchor mode for a funny effect. If you need details, check the current docs online.