It looks like it should be shortened but I can't see how.

I have my methods <= 5 lines but that's as far as I got:

def check_lines
  if horizontal?(@player) || vertical?(@player) || diagonal?(@player)
    @win=@player
  end
end

def horizontal?(player)
  ((@squares[0] == player) && (@squares[1] == player) && (@squares[2] == player)) ||
  ((@squares[3] == player) && (@squares[4] == player) && (@squares[5] == player)) ||
  ((@squares[6] == player) && (@squares[7] == player) && (@squares[8] == player))
end

def vertical?(player)
  ((@squares[0] == player) && (@squares[3] == player) && (@squares[6] == player)) ||
  ((@squares[1] == player) && (@squares[4] == player) && (@squares[7] == player)) ||
  ((@squares[2] == player) && (@squares[5] == player) && (@squares[8] == player))
end

def diagonal?(player)
  ((@squares[0] == player) && (@squares[4] == player) && (@squares[8] == player)) ||
  ((@squares[2] == player) && (@squares[4] == player) && (@squares[6] == player))
end