For the sequence \begin{equation} a_{k+1}=\begin{cases} a_k/2 & \text{if } a_k \equiv 0 \pmod 2, \\ 3a_k+1 & \text{if } a_k \equiv 1 \pmod 2. \end{cases} \end{equation} The Collatz conjecture is: \begin{equation} \forall\,a_0\in\mathbb{N}+1=\{1,2,3,\dots\}\\\,\exists\,k\ \text{such that}\ a_k=1 \end{equation}

I saw this video and thought of Collatz because the number of triangles in 2d Sierpinski is \(3n+1\) per iteration and the squares alignment makes me think of the division by 2.

I also think I remember \(1.58\) as the limit of a convergence rate for number of digits or something along those lines. Regardless, the analogy stuck better than most things I compare to this problem, so here's an orthographic visualization.

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In the square outline, the vertical lines of the wireframe have exactly 2 distances where a raycast crosses an edge. This is more clearly seen in the volumetric mode, where there are no overlapping surfaces facing out of the screen. The diagonal lines in the wireframe's projection have no parallel overlap.