I'm having some problems compiling a project which includes debris area fills. Depending on the exact symbol fill that I use, I am getting strange scale-dependant errors which seem to cause the compiler to loop endlessly until I force it to stop.

I originally noticed the problem when using a custom area fill that I made by modifying the standard a_debris_AUT symbol fill. I've attached my modified metapost definition in the attached text file 'a_debris_WUG.txt'.
The error occurs for any scale between 1:2000 and 1:4483 (outside of this range the project compiles fine).

See attached output log 'Output log - a_debris_WUG.txt'. As you can see, the file seems to loop over and over again.

Initially I thought this problem was specific to my custom fill, but then I noticed that I also get a similar error when using the standard a_debris_AUT fill, however this time the error only occurs when the scale is set to exactly 1:2000 (any other scale seems to be fine).

See attached output log 'Output log - a_debris_AUT.txt'.

Can anyone help with this problem?

Thanks

Tom