pen movement operators

Ck - set pen color to k

S - set origin, increment for the pen

U - set overall y-offset for the graph

A, a - zero multiple line offset, increment offset

G, H - move to first point, normal or hidden

g, h - move to additional point, normal or visible

s - push, then increment the pen position

There are several documents available explaining REC [1], including a read.me file in the rec subproject of each of the REC files.