SCREEN 12
  CLS
  c = .5 / SQR(3)
  r2 = SQR(3) / 2
  r3 = SQR(3) / 6
  ex = 300
  sx = 100
  sy = 100
  x = 1
  y = 0
  GOSUB po
  WHILE INKEY$ <> CHR$(13)
    IF RND(1) > .5 THEN
          x0 = .5 * x + r3 * y
          y0 = r3 * x - .5 * y
    ELSE
          x0 = .5 * x - r3 * y + .5
          y0 = -r3 * x - .5 * y + r3
    END IF
    x = x0
    y = y0
    GOSUB po
  WEND
  dummy$ = INPUT$(1)
  CLS
  END

po:
  PSET (x * ex + sx, sy - y * ex)
  u = .5 * x - r2 * y
  v = -r2 * x - .5 * y
  PSET (u * ex + sx, sy - v * ex)
  u = -.5 * x + r2 * y + 1
  v = -r2 * x - .5 * y
  PSET (u * ex + sx, sy - v * ex)
  RETURN