1. Visual task: compare the needle with the digital display
The needle steps one tick every second and its direction changes unpredictably. The rule is simple: the digital display must always show the needle value × 10 (needle on 7 → display 070).
Every so often the digital display shows a wrong value — usually it lags one step behind (the needle moves to 21 while the display stays on 200), sometimes it is off by ±10. The moment you spot a mismatch you press the EYE button; the display refreshes about one second later, so the reaction window is tight.