Lots of great ideas, Thank you! But MikeG, the pool table idea I'd really have to see.

Way back I was an analog computer repairman in the Air Force. After the Air Force phased out analog computers (which measure), in favor of the digital computer (which count) -based SAGE System, the Navy tried installing one of the analog systems (a GPA-37) on a ship. But like pool tables, analog computers must be level to work properly. So the Navy installed them on a gimbaled platform controlled by gyros in the hold of a ship. I was one of the AF guys who got to try and help the Navy make the thing work. We were making some progress out there in the north Pacific, that is until we got into a storm - not a real big storm, but one big enough so the gimbaled platform with the computer on it started rocking and rolling, and began to 'hit the stops' when a big wave came along. It hit the stops with a huge bang and a slamming jerk. And everyone: us, the navy petty officers working with us, even the officer in charge who rarely got on the platform but used to watch from the access port, got seasick. That was messy. Real messy. Messy as in to the computer bays! After that it was a total disaster. We sailed back to Bremerton, and us AF guys got off and would not get back on. We were threatened, and cajoled, and warned, but every one of us said NO, repeatedly. Then one guardhouse lawyer among us found an AF Reg that actually allowed airmen to refuse to serve on ships in some circumstances.

I never did hear what happened to that project (it was classified back then, ±45 years ago), but you could not keep that platform level in any kind of a sea, and being even a little level while your environment (i.e., the ship) was moving around you in three dimensions, in a closed space, was very disturbing to those bodily system(s) controlling the seasickness urge. Extremely disturbing. Sorry Mike, but I can't see how a pool table could be a whole lot different.

I will put it on the list. With reservations.