One oscillation per ear, alternating · sweep 0 → 178,000
Each cycle goes to one ear: 1→left, 2→right, 3→left… and the boxes switch at that same real frequency. Up to ~22 Hz the blink is synced to what you hear; above that it keeps switching at the true frequency but outruns your monitor's refresh and the eye's flicker fusion, so you'll see it aliased or as a steady glow.
Per-cycle panning. Each individual oscillation of the wave is sent to one ear and the next to the other, exactly at the frequency's rate. The left and right boxes turn on and off at that same real frequency: up to ~22 Hz the blink is synced to what you hear; above that it keeps switching at the true frequency but outruns what your monitor can repaint (~60–120 Hz) and the eye's flicker fusion, so you'll perceive it as aliased flicker or a steady glow. That limit is your screen and your retina, not the app. The oscilloscope shows both channels: one cycle in cyan, the next in amber.
⚠ 178,000 Hz is inaudible and cannot be generated. Human hearing reaches ~20,000 Hz, and digital audio can only generate up to the Nyquist limit (half your device's sample rate, ~22,050–24,000 Hz). Above that, the sound saturates and disappears. The number still sweeps the full range and the tag warns you as it crosses each limit.