When I read the file mfplain into Metapost, I get about a dozen error messages complaining about redundant and inconsistent equations. It's hard to believe that there is really anything wrong with mfplain. Any idea what might be going wrong ?
The details of the interaction are as follows:
C:\Program Files (x86)\MikTex\miktex\bin>mpost This is MetaPost, version 1.504 (MiKTeX 2.9) **\relax (mpost.mp (C:/Program Files (x86)/MikTex/metapost/base/plain.mp Preloading the plain mem file, version 1.004)) *\input mfplain (C:/Program Files (x86)/MikTex/metapost/base/mfplain.mp Preloading the plain base, version 0.99: preliminaries, basic constants and mathematical macros, macros for converting units, ! Inconsistent equation (off by 2.77794). <to be read again> ; l.230 mm*bpppix_=2.83464; pt*bpppix_=0.99626; ? [[ followed by a dozen or so similar messages ]]