Problem with arcs in gpic

[Michael Cain]

I'm having the following problem with drawing a series of arcs in  
gpic.  I'm running version 1.20.1, compiled from sources on Mac OS X  
version 10.5.8.  The following code draws a sequence of connected  
arcs, alternating in size, from top to bottom:

.PS
        arc  cw rad 0.075 to Here+(0,-0.15)
        arc ccw rad 0.025 to Here+(0,-0.05)
        arc  cw rad 0.075 to Here+(0,-0.15)
        arc ccw rad 0.025 to Here+(0,-0.05)
        arc  cw rad 0.075 to Here+(0,-0.15)
        arc ccw rad 0.025 to Here+(0,-0.05)
        arc  cw rad 0.075 to Here+(0,-0.15)
        arc ccw rad 0.025 to Here+(0,-0.05)
        arc  cw rad 0.075 to Here+(0,-0.15)
        arc ccw rad 0.025 to Here+(0,-0.05)
        arc  cw rad 0.075 to Here+(0,-0.15)
        arc ccw rad 0.025 to Here+(0,-0.05)
        arc  cw rad 0.075 to Here+(0,-0.15)
        arc ccw rad 0.025 to Here+(0,-0.05)
        arc  cw rad 0.075 to Here+(0,-0.15)
        arc ccw rad 0.025 to Here+(0,-0.05)
.PE

Part way through the sequence, the radius for the arcs gets messed  
up.  This happens in the output from gpic alone, shown here.  I tried  
the same experiment on an Ubuntu Linux box, also with gpic version  
1.20.1, and got the same result.

.lf 1 foo.mm
.lf 1
.PS 1.600i 0.100i
.\" -0.025 -1.6 0.075 0
.\" 0.000i 1.600i 0.100i 0.000i
.nr 00 \n(.u
.nf
.nr 0x 1
\h'0.100i'
.sp -1
\D't -1.000p'\h'1.000p'
.sp -1
\h'0.025i'\v'0.150i'\D'a 0.000i -0.075i -0.000i -0.075i'
.sp -1
\h'0.025i'\v'0.150i'\D'a 0.000i 0.025i -0.000i 0.025i'
.sp -1
\h'0.025i'\v'0.350i'\D'a 0.000i -0.075i -0.000i -0.075i'
.sp -1
\h'0.025i'\v'0.350i'\D'a 0.000i 0.025i -0.000i 0.025i'
.sp -1
\h'0.025i'\v'0.550i'\D'a 0.000i -0.075i -0.000i -0.075i'
.sp -1
\h'0.025i'\v'0.550i'\D'a 0.043i 0.025i -0.043i 0.025i'
.sp -1
\h'0.025i'\v'0.750i'\D'a 0.000i -0.075i -0.000i -0.075i'
.sp -1
\h'0.025i'\v'0.750i'\D'a 0.043i 0.025i -0.043i 0.025i'
.sp -1
\h'0.025i'\v'0.950i'\D'a 0.000i -0.075i -0.000i -0.075i'
.sp -1
\h'0.025i'\v'0.950i'\D'a 0.043i 0.025i -0.043i 0.025i'
.sp -1
\h'0.025i'\v'1.150i'\D'a -0.130i -0.075i 0.130i -0.075i'
.sp -1
\h'0.025i'\v'1.150i'\D'a 0.043i 0.025i -0.043i 0.025i'
.sp -1
\h'0.025i'\v'1.350i'\D'a -0.130i -0.075i 0.130i -0.075i'
.sp -1
\h'0.025i'\v'1.350i'\D'a 0.043i 0.025i -0.043i 0.025i'
.sp -1
\h'0.025i'\v'1.550i'\D'a -0.130i -0.075i 0.130i -0.075i'
.sp -1
\h'0.025i'\v'1.550i'\D'a 0.043i 0.025i -0.043i 0.025i'
.sp -1
.sp 1.600i+1
.if \n(00 .fi
.br
.nr 0x 0
.lf 18
.PE
.lf 19