Post_12.2.rb

player = ui.choice

if player == "E"
  player = computer_player
else 
  player = intel_computer_player
end

ui.welcome(board.cells, player)

until new_game.game_over?(board.cells)
  human_player.user_turn(ui)
  if board.invalid_key(human_player.answer)
    ui.user_error
  else
    board.valid_move(human_player.answer)
    player.possible_moves(board.cells) 
    board.computer_move(player.computer_move(player.possible_moves(board.cells)))
  end
end