:l = *[1]

:n = 0

:$ f(t)
	t!insert(len(l)+1)

	|f1: {l} {t}

	|CHECK
	merge branch!

	if(n < 1)
		|REC

		n += 1
		f(t)

		|END REC

	t!insert(len(t)+1)

	|f2: {l}

f(l)

|FINAL

|l: {l}