That&#x27;s not just an application for procedural cities, that&#x27;s Houdini (<a href="http:&#x2F;&#x2F;www.sidefx.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.sidefx.com&#x2F;</a>), a relatively well-known 3D modeling, animation and rendering tool based on the node-based (a.k.a. functional) approach. I investigated them, and while I found the tool itself very powerful, its language is not a proper general-purpose functional language, and I don&#x27;t think it&#x27;s turing-complete (if you exclude their integrated Python scripting).