PROTO p1 [
  ]{
  Box {}
  }
  
  PROTO p2 [
  ]{
  Sphere {}
  }
  
  PROTO p3 [
  ]{
  Transform { translation -1 0 0 children [ p1 {} ] }
  Transform { translation 1 0 0 children [ p2 {} ] }
  }
  
  p3 {}