const n:int = 100

type st = On | Off

node f(a:int^n at r; c:st) returns (o:int^n at r)
var u,v,x:int^n at r;
let
  (u, v) = split c (a);
  x = [ u with [0] = 0 ];
  o = merge c (On -> x) (Off -> v)
tel

node main() returns (o:int^4)
var c:st;a:int^n at r;
let
  o = (f(a,c))[0..3];
  c = Off fby Off fby On fby c;
  init<<r>> a = 1^n;
tel