#ignore + - \ / ^ &
#axiom
S(0,0)
#rules
S(a,c) : c>=50 -> S(a+1,0)
S(a,c) : c<50 -> G\(90)[-S(0,0)]S(0,0)
W(a) : a<7 -> W(a+1)
W(a) : a>=7 -> B