Reply to "spiral-curve-spiral"

Most of the curves on my layout-under-construction are eased.  The two under-table horseshoe curves are continuously variable radius, a bit above 112/104 at their ends, 96/88 at the 45° point, and 80/72 at their apexes, with 5" spacing at the apex and 4" at entry/exit.  I took a deep dive into the math of this two years ago and have a PDF discussion available that summarized my research.  The continuously-variable horseshoes were the key to fitting the desired track plan into the available space while keeping all visible mainline curves at 112/104.  Here's a pic of one of them, before the upper layer was added.