Risto A. Paju<p>In the last post, I noted how the incremental iterates of the Apollonian gasket look like the output of an iterated function system. There's indeed such an IFS, and it's a system of circle inversions. It's how I've made a lot of fractal art over the years, but I've usually started directly with the inversion circles/spheres themselves.</p><p>Now that I've worked with the "classical" approach to the Apollonian gasket, I thought I'd translate a given Apollonian setup to the language of inversions. It was a fun little exercise and the math was surprisingly simple, just playing with vectors and solving linear equations. I then used my old inversion shaders from the late 2010s to show the results.</p><p>The first part shows it all together: the 3 largest coloured circles are the initial Apollonian circles, and the 4 inversion circles can be seen in the darkest grey in the background. (The initial Apollonian circles also include a 4th one, but here we can only see it as the perimeter of the coloured area.)</p><p>The second part uses a pointillist process, and it shows essentially the incremental iterates of the previous post. The inversion circles are not seen, but the Apollonian circles are all there as the empty space.</p><p><a href="https://mathstodon.xyz/tags/apolloniancircles" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>apolloniancircles</span></a> <a href="https://mathstodon.xyz/tags/apolloniangasket" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>apolloniangasket</span></a> <a href="https://mathstodon.xyz/tags/iteratedfunctionsystem" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>iteratedfunctionsystem</span></a> <a href="https://mathstodon.xyz/tags/inversion" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>inversion</span></a> <a href="https://mathstodon.xyz/tags/circleinversion" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>circleinversion</span></a> <a href="https://mathstodon.xyz/tags/geometricart" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>geometricart</span></a> <a href="https://mathstodon.xyz/tags/fractal" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>fractal</span></a> <a href="https://mathstodon.xyz/tags/fractalart" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>fractalart</span></a> <a href="https://mathstodon.xyz/tags/pythoncode" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>pythoncode</span></a> <a href="https://mathstodon.xyz/tags/opengl" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>opengl</span></a> <a href="https://mathstodon.xyz/tags/algorithmicart" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>algorithmicart</span></a> <a href="https://mathstodon.xyz/tags/algorist" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>algorist</span></a> <a href="https://mathstodon.xyz/tags/mathart" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>mathart</span></a> <a href="https://mathstodon.xyz/tags/laskutaide" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>laskutaide</span></a> <a href="https://mathstodon.xyz/tags/ittaide" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ittaide</span></a> <a href="https://mathstodon.xyz/tags/kuavataide" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>kuavataide</span></a> <a href="https://mathstodon.xyz/tags/iterati" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>iterati</span></a></p>