You can’t make people use streets they have no reason to use. You can’t make people watch streets they do not want to watch. Safety on the streets by surveillance and mutual policing of one another sounds grim, but in real life it is not grim. The safety of the street works best, most casually, and with least frequent taint of hostility or suspicion precisely where people are using and most enjoying the city streets voluntarily and are least conscious, normally, that they are policing.
Street lights can be like that famous stone that falls in the desert where there are no ears to hear. Does it make a noise? Without effective eyes to see, does a light cast light? Not for practical purposes.
What's that big electrical cord that also connects the ship to the dock? It's not a power cord to run machinery aboard ship; it's a grounding strap, to prevent sparks from static electricity. Something else you're sure to notice on a tanker is a big warning sign about the fire hazard. Frederick Allen, the editor of American Heritage of Invention & Technology, has remarked that all tankers seem to be named No Smoking.
The patterns of Truchet's tiles appear at first glance as variously shaped interlocked regions of black and white, the boundaries between the square tiles being submerged whenever the two regions flanking them have the same color, just as in a real floor the air or cement between the tile edges is not perceived—until one looks closely. The scale of resolution determines what is seen.