Image of the ceiling texture in the <a href="//commons.wikimedia.org/wiki/Maintower" class="mw-redirect" title="Maintower">Maintower</a> on the floor below the observation deck.
<a href="//commons.wikimedia.org/wiki/User:ZeWrestler" title="User:ZeWrestler">ZeWrestler</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>