A slight correction: the technique existed long before the paper, so I wouldn&#x27;t exactly say that its the &quot;original&quot; paper.<p>The paper was written by Chris Lomont in 2003, when the gamedev.net community first started investigating the code (I thought Beyond3D did their investigation earlier, but it looks like they did it in 2004). There is a different paper that published a similar idea in 1997 (Floating Point Tricks), but its not the one linked. The code first appeared in the wild on comp.graphics.algorithms around 2002, apparently.<p>I remember this because I followed the discussion on Gamedev.net when Chris Lomont wrote his paper. Some years after, I found the Beyond3D articles where they traced the origin back to Ardent Computer.<p><a href="https:&#x2F;&#x2F;www.gamedev.net&#x2F;topic&#x2F;139956-carmacks-sqrt&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.gamedev.net&#x2F;topic&#x2F;139956-carmacks-sqrt&#x2F;</a><p><a href="http:&#x2F;&#x2F;www.beyond3d.com&#x2F;content&#x2F;articles&#x2F;8&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.beyond3d.com&#x2F;content&#x2F;articles&#x2F;8&#x2F;</a><p><a href="http:&#x2F;&#x2F;www.beyond3d.com&#x2F;content&#x2F;articles&#x2F;15&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.beyond3d.com&#x2F;content&#x2F;articles&#x2F;15&#x2F;</a>