Oh, right, I had remembered it backwards, and I didn't realize Eno got it from Riley and Oliveros! I guess my chain of provenance is missing a few. Of course, in the hands of any creative musician, I think it would only take a week or so before they thought about making a tape loop on a reel-to-reel recorder.

https://happymag.tv/frippertronics/:

"In September of 1972, the pair met in Eno’s London home studio, where he had set up a tape system developed by avant-garde composers Terry Riley and Pauline Oliveros."