20 shortish lines that do something fun.

whatisit.py

import itertools, os, sys

it, chars = 20, '.-=*x#X'
sys.stdout.write('\x1b[?25l')
w = int(os.popen('tput cols').read())
h = int(os.popen('tput lines').read()) - 1
x_max, y_max = float(w) / (2.0 * h) * 1.2, 1.2

for j in itertools.count(1):
    sys.stdout.write('\x1b[1;1H')
    x_max, y_max = x_max * 0.995, y_max * 0.995
    if j % 40 == 0: it += 1
    for y_ in range(h):
        y = y_max * (float(y_) / h * 2 - 1)
        for x_ in range(w):
            x = x_max * (float(x_) / w * 2 - 1)
            z, i, c = 0j, 0, x - 0.822 + y * 1j + 0.2j
            while abs(z) <= 2 and i < it:
                z, i = z * z + c, i + 1
            sys.stdout.write(' ' if i == it else chars[i % 7])