stein is a stone on your phone. tilt it and it moves.

it reads motion sensors. no value leaves this device, nothing is recorded, and there is no server to send anything to — after loading, the page works with the network unplugged.

hold still for a moment first, to measure how much your hand shakes. that is what decides when the stone is allowed to come to rest.

it needs a phone. a laptop or desktop has no motion sensor.

ios asks for permission once and remembers the answer. if you refused and want it back, it is in settings › safari › motion & orientation access.