Pan2 places a mono signal in a stereo field; its pos argument ranges from -1 (left) to +1 (right)
Pan2.ar(signal, pos, level) places a mono signal in a stereo field. The pos argument ranges from -1 (hard left) to +1 (hard right), 0 at center. Because SinOsc is bipolar (-1..+1), it can be used directly as pos to auto-pan continuously. This is a common live-coding idiom: modulating pos with an LFO creates automatic panning. Pan4 extends to quad; PanAz handles arbitrary channel counts. A single Pan2 always outputs exactly 2 channels regardless of upstream multichannel expansion.
Examples
p = {Pan2.ar(PinkNoise.ar, SinOsc.kr(2), 0.1)}.play; // auto-pan 2 Hz
p.free;
Assessment
Write a patch where a sawtooth wave is auto-panned at 1 Hz using Pan2 and a SinOsc LFO. Modify it so pan speed is controlled by MouseX.