I did it with python3 -c "`echo -e 'import time\nwhile True:\n print(u"\u2571\u2572"[int(time.time() * 100)%2],end="")\n time.sleep(0.001)'`" The neat thi

I did it with python3 -c "`echo -e 'import time\nwhile True:\n print(u"\u2571\u2572"[int(time.time() * 100)%2],end="")\n time.sleep(0.001)'`" The neat thing about it is that the randomness comes from the inexactness of time.sleep