Flat Line
An infinite, one-input game about guessing the next value: drag to predict, and a flat line you never see is guessing too.
Drag to predict the next value.
A noisy series lands a new value every half second, and the height of your finger is your guess for the next one. Beside you, unseen, a flat line, the average of the last ten values, guesses the same values.
Nothing gets harder. The series moves the same way at the first value and the thousandth. The run ends when the flat line's error over the last 30 values beats yours by a fifth.
The card sets your error beside the flat line's, and draws the last 60 values with the flat line in white: the line that was never on screen while you played.
Canvas2D, so the game is whole on any phone. No camera, no account, and nothing leaves the machine.