#axiom
l(1)
#rules
#L->lR
l(a) : a>= 1 -> l(0)r(0.5)
#R->Lr
r(a) : a>= 1 -> l(0.5)r(0)
#l->L
l(a) : a < 1 -> l(a+0.1)
#r->R
r(a) : a < 1 -> r(a+0.1)
#end rules