Description of Problem:
Elements which should be of the same size are not and dependency
on a size parameter is not even linear.

The bug affects gnuplot-3.7.1, and also a test version 3.8.0 from
www.gnuplot.org, hence distributions at least from 6.2 are affected.
A version 3.7 of gnuplot (hard to find nowadays) does not seem to have
this bug.

How Reproducible:
100%


Steps to Reproduce:
Run the following bash script:

#!/bin/sh

for n in $(seq 30 39) ; do
    sed "s/XX/$n/" bug.in > bug.gp
    gnuplot bug.gp
done

on an attached file bug.in. Look at produced Postscript files with gv
and note how squares on the left and on the right are changing sizes
on different pictures.