🚀 go-pugleaf

When I use METAFONT lanuguage to generate a logo font, I met
a strange problem when I tried to print it, only for a certain range 
of size of the logo (for small and large size), the dvips program works, 
but in the middle range, dvips doesn't work, I tried every method
to get rid of this problem, including change the magnification
parameter, or the basic unit of the quantity determain the logo's
size, I even tried multiply a constant to all the coordinates of
the points, but none of them success. My program is very simple, drawing
part only involes one command "draw", it's a short programm (I
simplified the program, when the programm is as short as 21 lines
, I still have the trouble), I can draw every part of the logo, but
when I put them together, the trouble comes, it's really strange, 
anyone can give me some suggestion?
Thank in advance.
Ze Yang