:x = [99] :l = [1,x] :n = 0 $ f(t) ~ t!insert(len(l)+1) f1: {l} {t} CHECK § c ~ n < 1 REC ~ n += 1 ~ f(t) END REC f2: {l} CHECK 2 § d ~ t!insert(len(t)+1) ~ t(2)!insert(len(l)+1) f3: {l} {t} ~ f(l) FINAL l: {l} x: {x}