Each one measures or computes something real. None of them needs a network.
Your phone sweeps a tone into the room and listens to what comes back, to time the echo.
needs the microphone
The back camera watches still air and measures how fast your hand shakes, in hertz.
needs the camera
Twelve perfect fifths do not fit seven octaves. Tune one by ear and hear the gap.
needs sound on
Thousands of blind agents build a network between your food. None of them sees the map.
tap to place food
Two identical pendulums, a billionth apart, and a clock that measures when they stop agreeing.
drag to swing
Tap out any pattern of lights. It hands you the moves, or proves no set of moves exists.
tap the lights
Same pixels, same colours, shuffled. A compressor in the page tells you which one it can read.
draw with a finger
A fingertip over the camera and the flash. It reads your heart rate from the light coming through.
needs the camera
A click every half second. Tap along and it tells you how early you are and how steady.
needs sound on
A small network learns the shape of the dots you place, and shows you where it fails.
tap to drop dots
no accounts · no tracking · nothing is sent anywhere