restraints plane {<restraints-plane-statement>} end

<restraints-plane-statement> :==

  initialize
  --{Turn off plane restraints and delete all previous entries.} 
  group <restraints-plane-group-statement> end
  --{Define a new plane group.}
  ?
  --{Print the plane setup.}

  --{The following symbols are created: $planx, $plany, $planz.
     These define the normal vector of the plane defined by the last group.}