Pins and tails along a seam: the planar ancestor of the universal joint. Flare is how hard the lock bites; columns is how many keys fit the run.
The planar ancestor: pins and tails along a seam. Flare is the undercut that stops the joint pulling apart; columns is how many keys fit the run. Stacked courses are a timber wall, or a wallpaper of lock. Odd rows slide in motion — a sliding dovetail walking its groove.
tilinggrid
PinWide at the tip so it cannot pull out. Repeat along a seam and the boards lock.