<?xml version="1.0"?>
<!-- common rock settings -->
<PropertyList>
  <xsize>500</xsize>
  <ysize>500</ysize>
  <solid>1</solid>
  <friction-factor>0.9</friction-factor>
  <rolling-friction>0.1</rolling-friction>
  <bumpiness>0.3</bumpiness>
</PropertyList>