axiom
    G(-5,5,5)
    X(90) Y(90) Z(90)
    S(8)
    c;

rules 3
   c=c
    [ S(S*0.5)f>-f>-f>- c ]
    [ S(S*0.5)-f>-f^f++ c ]
    [ S(S*0.5)-f+f^f&   c ];           
end

rules 1
    c=[(F-F-F-F-)<+(F-F-F-F-)<+(F-F-F-F-)]
      [f&(F-F-F-F-)f][-f&+(F-F-F-F-)]
      [f&f& (F-F-F-F-)];
end