-- take n xs: first n elements of a list or text.
-- drop n xs: skip the first n; return the rest.
-- Both truncate (no error) when n exceeds the length.
-- Negative n raises a runtime error.
first-two xs:L n>L n;take 2 xs
rest-after-two xs:L n>L n;drop 2 xs
head3 s:t>t;take 3 s
tail-from2 s:t>t;drop 2 s
-- run: first-two [1,2,3,4,5]
-- out: [1, 2]
-- run: rest-after-two [1,2,3,4,5]
-- out: [3, 4, 5]
-- run: first-two [1,2]
-- out: [1, 2]
-- run: rest-after-two [1,2]
-- out: []
-- run: head3 "hello"
-- out: hel
-- run: tail-from2 "hello"
-- out: llo