iex> f = fn(x) -> x * x end
#Function<6.54118792/1 in :erl_eval.expr/5>
iex> f.(2)
4
iex> g = &(&1 * &1)
#Function<6.54118792/1 in :erl_eval.expr/5>
iex> h = fn(x) -> x + 1 end
#Function<6.54118792/1 in :erl_eval.expr/5>
iex> f.(2)
4
iex> g.(2)
4
iex> h.(1)
2