  COMMAND PEXPLODE
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    Purpose: create a realistic particle-explosion
      Usage: PEXPLODE(<particleID>,<frames>,<filename>,
             <time>,<gravity constant>,<eta (Stokes)>,<v0>,
             <maxRot>,<saveFormat>)
   Examples: pexplode(1,180,hd1:objects/obj,12,-10.0,-0.0001,42,9,particle)
             pexplode(1,48,obj,12.8,-10.0,-0.001,52,7,obj)
