L2TAN, NL1, NL2
Generates a line tangent to two lines.
NL1Number of the first line generated line is tangent to. If
negative, assume P1 (see below) is the
second keypoint of the line instead of the first. If NL1 =
P, graphical picking is enabled and all remaining command fields are ignored
(valid only in the GUI).
NL2Number of the second line generated line is tangent to. If
negative, assume P3 is the second keypoint
of the line instead of the first.