Read about the geometric operator ":". This has been discussed many times in the past and can be found multiple times in the forum.
Basically
XP:shift ; shift in tool
shift:XP ; shift in baseFubini
If you are new and/or in a hurry reading about bases might be quicker/easier.
Do keep in mind offsets with geometric operator will not stop advance run pointer, while changing $base - will.
This might be helpful. The GridFunctions module performs Base adjustments based on X, Y, and Z counters (using the Geometric Operator), and the GridExample program is a program that uses the GridFunctions module.
...hm. Looking at it again, I can see I need to update the example program. I wrote it for someone who needed a unique Rz rotation for the first row, so two different pick positions were taught. Still, this should demonstrate the basic operation well enough.
