The vertical part of it looks like the shape of a Winston Cone, an off-axis parabolic shape that is used nowadays in high energy particle physics experiments as a light guide to direct photons to a photomultiplier tube. Two partners and I designed those things for Project MIPP, a sub project for Project MINOS at FermiLab. Winston cones only have about a 3% loss of photons in transmission.
Anyway, that's another thing it reminds me of.
Mike
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Sandpaper gets the job done, but makes for a lot of friction.
Version 2 of the "Winston-Cone-Base" has a slightly bigger disk and elevated higher than the v1 base. It still doesn't extend beyond 32mm perimeter of the hex and it's fairly stable.
My goal is to come up with a base that is stable, not distracting, not ridiculously huge like the 2500 bases and not $2 a pop. I'm not digging the clear bases. The 2400's are probably the better playing pieces for hex maps I already have.