Upr 5
┌─
╵ 1 1 1 1 1
  0 1 2 3 4
  0 0 1 3 6
  0 0 0 1 4
  0 0 0 0 1
            ┘
  Lwr 5
┌─
╵ 1 0 0 0 0
  1 1 0 0 0
  1 2 1 0 0
  1 3 3 1 0
  1 4 6 4 1
            ┘

  Sym 5
┌─
╵ 1 1  1  1  1
  1 2  3  4  5
  1 3  6 10 15
  1 4 10 20 35
  1 5 15 35 70
               ┘