def perms(positions: List[Int]) = {
        val x: Set[List[Int]] = positions.permutations.map(_.take(2)).toSet

        val y = x filter {
          case a :: b :: Nil =>
            (a, b) match {
              case (a: Int, b: Int) if a < b => true
              case _ => false
            }
          case _ => false
        }

        System.out.println(y)
      }

      (4 until 9) foreach { length =>
        perms((0 until length).toList)
      }

      /*
Output:
Set(List(1, 2), List(2, 3), List(0, 2), List(0, 1), List(1, 3), List(0, 3))
Set(List(3, 4), List(1, 2), List(2, 3), List(1, 4), List(0, 4), List(0, 2), List(2, 4), List(0, 1), List(1, 3), List(0, 3))
Set(List(3, 4), List(0, 5), List(1, 2), List(2, 3), List(1, 4), List(0, 4), List(0, 2), List(2, 4), List(0, 1), List(1, 5), List(2, 5), List(4, 5), List(1, 3), List(3, 5), List(0, 3))
Set(List(3, 4), List(0, 5), List(1, 2), List(2, 3), List(1, 4), List(5, 6), List(0, 4), List(0, 2), List(2, 4), List(0, 1), List(1, 6), List(1, 5), List(2, 5), List(4, 5), List(2, 6), List(1, 3), List(3, 5), List(0, 3), List(4, 6), List(3, 6), List(0, 6))
Set(List(3, 4), List(0, 5), List(1, 2), List(2, 3), List(1, 4), List(5, 6), List(0, 4), List(1, 7), List(0, 2), List(4, 7), List(2, 7), List(2, 4), List(0, 1), List(0, 7), List(1, 6), List(6, 7), List(1, 5), List(2, 5), List(5, 7), List(4, 5), List(2, 6), List(1, 3), List(3, 5), List(0, 3), List(4, 6), List(3, 7), List(3, 6), List(0, 6))
      */