For years and years, campers have enjoyed inventing fun responses to being bopped on the hand.
a(b(
)) = 
c(d(
)) = 
a(e(f(
))) = 
g(h(d(
))) = 
i(e(g(
))) = 
i(e(d(f(
)))) = 
c(e(b(a(
)))) = 
i(a(b(d(c(
))))) = 
h(e(f(e(h(
))))) = 
g(c(d(h(f(
)))))
a(e(i(d(
))))
f(g(c(
)))
h(g(a(f(g(
)))))
i(a(g(h(
))))
b(e(b(i(f(
)))))
e(g(b(h(
))))
e(g(d(i(f(
)))))
b(e(b(e(b(e(b(
)))))))
b(g(i(d(
))))
e(c(h(
)))