Thinking about an alternate history tech timeline where TVs used a spiral scan instead of a raster scan. The lore is that Farnsworth had the insight that led to raster scan while thinking about farm furrows, but it seems like the continuous smooth variability of a spiral pattern might have been friendlier to the analog technologies of the day, as well as having the analogy to record players. There would have been some objective advantages: Vacuum tube CRTs “want” to be round, and were only made square-ish with bezels and significant effort. Keeping the beam on continuously, without blanking for horizontal retrace, gives better resolution for a given bandwidth. You could scan both in and out for zero blanking, but you would get some crossing intensity artifacts, so probably best to still do one sync pulse per frame. You could still interlace spirally for temporal resolution enhancement. It would be easy to increase the resolution in the center of the screen, which would probably be a net win. You could intensity compensate for a sparser or faster scan at the edges, or just let it naturally vignette. However, it would have been terrible as a digital computer display, so maybe we dodged a bullet there. Still maybe interesting for laser displays today, where sophisticated resampling is trivial.