This is slightly irrelevant but presumably someone could invent a version of Metropolis that also distributed its rays across time as well as space, thereby ens

This is slightly irrelevant but presumably someone could invent a version of Metropolis that also distributed its rays across time as well as space, thereby ensuring that any bright/flickery pixels would remain coherent across frames; i.e. once that path was discovered on one frame, it could propagate that path information out to previous/succeeding frames.