Source code in the 11l programming language

F e(&x, row, col) -> &
   R x[row * (row + 1) I/ 2 + col]

F iterate(&v, &diff, do_print = 1B)
   V tot = 0.0
   L
      e(&v, 0, 0) = 151
      e(&v, 2, 0) = 40
      e(&v, 4, 1) = 11
      e(&v, 4, 3) = 4

      L(i) 1..4
         L(j) 0..i
            e(&diff, i, j) = 0
            I j < i
               e(&diff, i, j) += e(&v, i - 1, j) - e(&v, i, j + 1) - e(&v, i, j)
            I j != 0
               e(&diff, i, j) += e(&v, i - 1, j - 1) - e(&v, i, j - 1) - e(&v, i, j)

      L(i) 1..3
         L(j) 0.
            e(&diff, i, j) += e(&v, i + 1, j) + e(&v, i + 1, j + 1) - e(&v, i, j)

      e(&diff, 4, 2) += e(&v, 4, 0) + e(&v, 4, 4) - e(&v, 4, 2)

      L(i) 0 .< v.len
         v[i] += diff[i] / 4

      tot = sum(diff.map(a -> a * a))
      I do_print
         print(‘dev: ’tot)
      I tot < 0.1
         L.break

V v = [0.0] * 15
V diff = [0.0] * 15
iterate(&v, &diff)

V idx = 0
L(i) 5
   L(j) 0..i
      print(‘#4’.format(Int(0.5 + v[idx])), end' I j < i {‘ ’} E "\n")
      idx++