0 QTRS
rev(nil) → nil rev(rev(x)) → x rev(++(x, y)) → ++(rev(y), rev(x)) ++(nil, y) → y ++(x, nil) → x ++(.(x, y), z) → .(x, ++(y, z)) ++(x, ++(y, z)) → ++(++(x, y), z) make(x) → .(x, nil)