type Element { E | A | B | C }

; see: https://mathworld.wolfram.com/Vierergruppe.html
mult : Element Element -- Element
     =: [
        { case
            | E ->
            | A -> { case | E -> A | A -> E | B -> C | C -> B }
            | B -> { case | E -> B | A -> C | B -> E | C -> A }
            | C -> { case | E -> C | A -> B | B -> A | C -> E }
        }
]

%foreign kabi mult