Someone told me that in medieval China and Japan, incense clocks burned different scents throughout the day, so you could smell the time.
Did people take it for granted: that's the way we do it, or did they marvel at the clever combinations? Were they trained, like Pavlov's dogs, to know it was, say, 9 o'clock when cinnamon wafted through the room? Could you torture someone or deprive them of sleep by lighting the early a.m. scent hour after hour? Would it influence people to experience synesthesia, the phenomenon of sensory "crossovers," like seeing letters as colors.
I remember I invented the AromAlarm, designed to wake you with the scent of coffee, but of course I didn't build it & was mostly pleased with the name. It's not a bad idea.