<a href="https://en.wikipedia.org/wiki/Arecibo_message" class="extiw" title="w:Arecibo message">Arecibo message</a>, represented with one pixel per bit. 23 × 73 pixels = 1679 pixels (the length of the Arecibo message).
<a href="//commons.wikimedia.org/wiki/User:Pengo" title="User:Pengo">Pengo</a>
2014-01-19 18:00:00
<span class="int-own-work" lang="en">Own work</span>