$ lumo -e '(+ 4 5 6) (+ 3 4 5)'
15
12

$ plk -e '(+ 4 5 6) (+ 3 4 5)'
Execution error (Error) at (<cljs repl>:1).
(((4) + (5)) + (6)) is not a function. (In '(((4) + (5)) + (6))(((3) + (4)) + (5))', '(((4) + (5)) + (6))' is 15)