circle.dc

var mybuf
80 24 * mkbuf
mybuf !

: bufadd
  over mybuf @ + swap 1 memset drop
;

: circle-draw
  1024 times
    0
    24 times
      80 times
        i 80 1.666 / / 0.8 - dup *
          j 24 / 0.5 - dup *
        + sqrt
        # radius
        k 32 / pi * cos 0.5 * 0.5 +
        0.46 *
        < if 42 else 32 endif bufadd
        1 +
      again
    again
    mybuf @ 80 24 * +   0   1   memset drop
    mybuf @ print
    drop
    0.0384 sleep
  again
;

circle-draw