Nautilus Shell (Ursula Seashell without cutouts or ring)

TL;DR: this is a remix of Nautilus Shell by @tc_fea that has been scaled and mirrored to be identical to the Ursula Seashell design by @Firepixie, only lacking the cutouts and necklace ring of the latter.

I recently decided to build a second one of these Adafruit Ursula's Seashell Necklace kits designed by Erin St Blaine (firepixie), but this time I'm building a tiny battery charger (and some extra circuitry for changing to "charging mode" when plugged in) into the design for added convenience. When I made the first one of these about 6 years ago, I realized that charging the battery was really inconvenient, and I didn't like the large cutout in the back of the shell. Hence the need for this remix.

I first set out trying to "repair" @Firepixie's original model to reconstruct the cutout section and quickly realized that was a loosing battle. After that, I scoured Thingiverse for every nautilus shell model I could find, hoping to find a suitable alternative. When I came across @tc_fea's model I realized it was identical (except for scale and tweaks) to the Ursula Seashell model.