StarMade Chessboard - I've not seen one, anybody know of one? I'm gonna build one for the heck of it, but hey, might be cool to see somebody else's.
You have the pieces - as artsy as you want, could even be just letters. Your setup is a double gridwork: one, a grid of sunken rails, so the dockers are hidden from as many angles as possible; the other, the visible black/white squares. Your playing method: you have a single OPERATOR controlling every single rail in the system. Players announce their moves, operator activates the correct rail switches to change Intersections and Paths to move pieces. It'd be slow-ish, but if the operator knew what they were doing, you'd just wait for the rails. Now, the Paths are between Intersections, which are 5 rails (center and 4 outside it, which are ALWAYS facing inside when not being used to maneuver a piece). Intersections hold pieces; Paths are any rails in between them, at least one and no more than 5 cause that gets insanely slow. Paths have 2 flips; they'll need an identifier, perhaps a colored block beside them in the center. These link to buttons available both in the hotbar and the logic field (set next to playing field for easy access for bugfixing), appropriately identified on both; these flip one way, and back. Intersections are trickier. First, you align the center block, then the outer block to the correct direction, necessitating 4-5 logic buttons each. It gets simpler if I link the COLUMNs and ROWs; a push sets all of column 1 to DOWN, a second push puts them all UP; horizontal rows do the same.
There, now that's better than my previous thought of tons and tons of buttons.
Centers are going to require 3 buttons: Left/Right/Down, and UP (towards White, I'll say, or towards Black, whatever) will be default; switch back at all times. I'll have to have a workaround for the rail above it - I'll need to be able to set that to move. Perhaps an UP button on the center that switches that to up. Clicking the button again switches it back; then the other Intersection rails (3 others around center) don't need to be set differently to point center by default, and then switch.
Now then, once you can move pieces, you need a method to get remove other pieces. This is a beam weapon, above each intersection. Each piece has a rail docker in the center, and a logic-fired Push Pulse to move it along, or a pull cannon could be fired at it. The beam weapon is because it looks cool and has two functions: One, down 50% of the Board's shielding; Two, break the docker. Then, it can cause shield damage to the Board, giving the shield effect as the piece drifts upwards under power, until it hits the beam weapon itself and (ideally) sticks on it. This necessitates large pieces, or a gap down them to the docker, so they can be removed in an awesome fashion. This gap can also catch on the beam weapon rod above it, sticking the piece in easy retrieval distance. Or just throw it to space so you can eliminate multiple pieces from there. That's probably better. Oh, and this beam weapon has to be separate from the other two entities - piece and board. Gonna need some work. It could just be the beam weapon fires and the piece floats away because the logic activates the rail, but that's less fun and more sensible.
To get the Knight past other pieces, I think easiest is to work him all the way around the board around them, but I know this won't always function. However, short of jumping in and flying it around, I have no easy ideas right now, so I'll work on it.
Stupid-complicated workaround: Knights are based on a SECOND full grid beneath the first, and the piece itself is attached to a second entity with a VERTICAL rail setup to move them up and over other pieces on this second grid, which will just be a second copy of the first, but beneath it and attached to all the same logic. The Knight has a special button to move it up and down on command. Necessitates much wireless logicky-ness and messy crud, but it's workable. Although the second rail setup will need to be significantly far down for the knight to move out of the way of other pieces when it's taken ... ahhh, dangit.
This is gonna take awhile and be very, very fun. I'm building one now!
Quick question: Does turning a rail to point, say, vertically (into or away from the docker) undock the entity on it?