This is a great idea and solves a major design problem with the P2S to allow complete capture of the toxic fumes! I have one major suggestion: The filament poop bin has a narrow opening at the top, which makes it impossible to reach your hand in. Its print orientation requires that the entire floor be a bridge, which doesn't come out as a smooth surface. What I would do instead is make the top opening as wide as possible and use 35 degree slope from the side walls to the overhanging top surface, so that the poop bin can be printed in upright configuration with minimal or no bridging. Also, having a sloped ceiling at the top would mean that all of the poop easily shakes out when its turned upside-down. I hope all of this makes sense after translating!

Printed well. There were one or two spots where there should have been support and there wasn't so there were 2-3 layers of droopy filament. I love this model and am curious if it's a generic model or pulled from someone's personal CT scan, because the vertebrae are asymmetric. I printed and cleaned it, immediately got really worried about not being able to keep track of assembly order, then immediately learned in a much more experiential way how facet joints fit together! No particular reason for me to have this around the house so I gave it to a PT I know. I'm tempted to cross the bridge to printing with TPU to do a version with discs.

A simple item but just absolutely nailed the design details. There is just one way that this could be better, which is instead of including an inset for a gasket (or maybe it's meant to be a sealing surface itself), actually reproduce the wedge-style beefy sealing ring like Nalenge bottles and some commercial lids use. See photo.

Top notch, though the indents for the fingers don't line up with mine whatsoever.

Had fun with this! The gears catch a bit and have noticeable friction, compared to a non-gear pull copter design I've played with. I would love to see a design that's in between the two you have (print-in-place and requires-metal-parts): one that has the tight tolerances only available if parts are assembled and gears/shafts printed separately for oriented strength, but doesn't require non-printed parts. In any case amazing design, super impressed that it works so well as print-in-place!