This example is essentially the same as "Basic RAM recording into buffer~", except that it's designed for recording and playing back a stereo signal instead of a single channel of audio. The buffer~ object has an additional argument to specify 2 channels of storage.
This pan~ subpatch takes one signal in the left inlet, and sends it out each of two outlets. The amplitude gain for each outlet is determined by a panning value supplied in the right inlet. This value can be supplied as a typed-in argument in the main patch, as a float value, or as a control signal.
This abstraction allows you to adjust the balance between two channels of audio. The audio channels come in the first two inlets, and a control signal comes in the right inlet. When the control signal is 0, the two channels pass through unchanged. As the control signal approaches -1, the amplitude of the right channel is reduced (till completely silent at -1) while the left channel remains unchanged; as the control signal approaches 1, the amplitude of the left channel is reduced (till completely silent at 1) while the right channel remains unchanged.