If you didn’t know this was Pink Floyd, you would never guess that this is Pink Floyd. Clearly, they had a unwalked road ahead of them as an excellent heavy metal band, but they chose to leave it unwalked. The musical landscape would have been markedly different if they’d followed this particular muse, though. Heavy metal would be a genre known for its intellectual clout and cutting-edge experimentation. Psychedelic and prog rock would be the domain of hairy morons who scream about pussy. And maybe if the single had been a hit, that’s what would have happened. But in 1969 Pink Floyd were still a few years out from having any hits, so they didn’t feel especially tied to any formula that might serve them. This remains a tantalizing one-off.