Consider `f : {1, 2, 3} ->{a , b , c}`and `g : {a , b , c} ->{a p p l e , b a l l , c a t}`defined as `f (1) = a`, `f (2) = b`, `f (3) = c`, `g(a) = a p p l e`,`g(b) = b a l l a n d g(c) = c