I had something similar on nitrous oxide, except that there was this sense that there were parts, like crystals, which were made to slot together and they were

I had something similar on nitrous oxide, except that there was this sense that there were parts, like crystals, which were made to slot together and they were hooking back to each other, one by one, and each addition added some kind of functionality. Unfortunately, the whole thing was rather fast -- I come out of general anesthesia like a shot, I am told -- and I was unable to observe more than that.