> Stefan’s paper asks what would happen if we could just stick a direct wire between certain pairs of LUTs, like you can when designing fully-custom hardware. It’s a hypothetical question, of course, because FPGAs don’t actually allow this.

Granted, it's been almost 30 years since I touched an FPGA, but are Long-Lines not a thing anymore? They were a limited resource, but as I recall they did make it possible to make fast long-distance connections.