!YS-v0

n =: 16
loop i 0:
  shell: 'clear'
  each y range(n):
    each x range(n):
      print:
        if bit-xor(x y) < i: +
          "█" " "
    print: "\n"
  flush:
  sleep: 0.15
  recur: i.++ % n.++