#axiom
I(2,1)
I(1,1)
S
#rules
I(a,b) : a == 3; b <= 5 -> R(1)I(1, b + 1)
I(a,b) : a == 2; b <= 5 -> R(1)I(2, b + 1)
S -> Z\(90)[-S]S
R(a) : a < 5 -> R(a+0.15)
#end rules