Calculate R2, phi1k, phi2k from 1) X=const and 2) Y=const arcs "depths"
Add .gitignore
Measure Xperp, R1 by fitting the measured distances between points

Use gp-dat-perp.awk on geom-cal.dat to produce geom-cal.dat.gpinc to feed it to gnuplot:
./gp-dat-prep.awk geom-cal.dat > geom-cal.dat.gpinc
Put the new geometry parameters; rescan table; fit table z-scan & put its parameters

Change table z-geometry -> needed to rescan.
XY geometry parameters -> robot_geom.py
Z parameters -> marlin_ak.py
Forgotten file: the last z-probing results
1. Improve line drawing; 2. Peano curve drawing code (buggy)

Line drawing: 1. first position pen, then move it down; 2. Absolute positioning using o constant = origin coordinates.