🚀 go-pugleaf

I have been trying to generate gf fonts with Metafont and the standard
cmfont sources.  On half the fonts, everything seems to work out OK; on
the rest, I get peculiar error messages like the following:
............................................................
}This is METAFONT, C Version 1.5 (no base preloaded)
}(cmbx7.mf (roman.mf (romanu.mf [65] [66] [67] [68] [69] [70] [71] [72] [73]
}[74] [75] [76] [77] [78] [79] [80] [81] [82]
}> 0 WSW 1 SSW WSW 2 (WNW NNW) NNE 3 ENE NNE 0 (NNW WNW)
}! Strange path (turning number is zero).
}<to be read again> 
}                   ;
}l.509 ...stroke z1e{x2-x1,10(y2-y1)}....{left}z2e;
}                                                    % upper arc
}? The path doesn't have a counterclockwise orientation,
}so I'll probably have trouble drawing it.
}(See Chapter 27 of The METAFONTbook for more help.)
............................................................
 and:
............................................................
}This is METAFONT, C Version 1.5 (no base preloaded)
}(cmex10.mf (mathex.mf (bigdel.mf [0] [16] [18] [32] [48] [64] [66] [1] [17]
}[19] [33] [49] [65] [67] [2] [104] [20] [34] [50] [52] [54] [3] [105] [21]
}[35] [51] [53] [55] [4] [106] [22] [36] [5] [107] [23] [37] [6] [108] [24]
}[38] [7] [109] [25] [39] [8] [110] [26] [40] [56] [58] [60] [62] [9] [111]
}[27] [41] [57] [59] [61]
}! bad pos.
}<to be read again> 
}                   ;
}pos->...XPR3)<=currentbreadth:errmessage"bad pos";
}                                                  fi.fi(x(SUFFIX2)r-x(SUFFIX...
}l.436 pos1(min_breadth,90)
}                          ; pos1'(min_breadth,90);
}?
............................................................

Note that the "zero turning number" error occurs while processing cmbx7.mf,
but not for cmbx10.mf.  Note also that it occurs while reading the romanu.mf
file, which is common to both cmbx7 & cmbx10.  I am stumped, and don't know
enough about Metafont to figure this out myself.  Is my version of Metafont
out of date?  What if I just type R & keep processing the font?  Is there
anywhere I can get an up-to-date C-version (not WEB) of Metafont & cTeX?

Thanks.
Paul Kirkaas
kirkaas@cs.ucla.edu