The game can be played in an iex session:
iex -S mix
Moves are played using the TTT.place/1 function:
19:03:01.180 [info] Player o begins.
Interactive Elixir (1.6.3) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> import TTT
TTT
iex(2)> place(:mm)
19:03:09.113 [info] The current state of the board is: %{ll: :empty, lm: :empty, lr: :empty, ml: :empty, mm: :o, mr: :empty, ul: :empty, um: :empty, ur: :empty}
19:03:09.113 [info] Player x's turn.
{:ok, {:mm, :o}}
Valid positions are defined according to the first letter of upper, middle, and lower followed by the first letter of left, middle and right as atoms.
[:ul, :um, :ur,
:ml, :mm, :mr,
:ll, :lm, :lr]