graphics in pdf not displayed correctly

[Dietrich Bollmann <diresu web de>]

Hi,

When opening a pdf file with evince some graphics are
randomly displayed (and printed) in a distorted manner. 
I appended four screen shots (only the graphics) made
after opening the same document ( 
http://www.vision.ee.ethz.ch/~pmueller/documents/mueller.procedural_modeling_of_buildings.SG2006.print-version.pdf 
)
four times.

Any help?

Thanks, Dietrich