node main (i: int) returns (o1: int);
let
    o1 = 10 -> pre (20 -> 30);
tel

node flipflop(i: int) returns (z: int);
var x, y: int; c: bool;
let
	c = true fby (not c);
	x = 1 on c;
	y = 2 on (not c);
	z = merge c x y;
tel