[]
[1, 2, 3, 4]
[1, 2] ++ [3, 4] # -> [1,2,3,4]
hd([1, 2, 3, 4]) # -> 1
tl([1, 2, 3, 4]) # -> [2,3,4]
[head | tail]
[1 | [2, 3, 4]] # -> [1,2,3,4]
[1 | [2 | [3 | [4 | []]]]] -> [1,2,3,4]
'hello' = [?h, ?e, ?l, ?l, ?o]
keyword_list = [a: 123, b: 456, c: 789]
keyword_list[:...