cellSet heater new boxToCell (-0.01    0 -100 )(0.01 0.01 100)
cellSet heater add boxToCell (-0.01 -100 -0.01)(0.01 0.01 0.01)
cellSet leftSolid new boxToCell (-100 0 -100 )(-0.01 0.01 100)
cellSet rightSolid new boxToCell (0.01 0 -100 )(100 0.01 100)
cellSet topAir new boxToCell (-100 0.01 -100 )(100 100 100)
cellSet bottomAir clear
cellSet bottomAir add cellToCell heater
cellSet bottomAir add cellToCell leftSolid
cellSet bottomAir add cellToCell rightSolid
cellSet bottomAir add cellToCell topAir
cellSet bottomAir invert