Exotic Delights Socks

There was a lot of mystery around the release of "Unknown Pleasures". A debut album, with no names or pictures of the band, no explanations, and no internet in 1979 to find out.
What were those lines? What did they represent? Mountains? Waves?
Today our lives are easier, and any search engine will help us find the January 1971 edition of Scientific American magazine, and Harold D. Craft Jr’s Ph.D. thesis on “Radio Observations of the Pulse Profiles and Dispersion Measures of Twelve Pulsars”.
Then the original image was republished in the 1977 Cambridge Encyclopaedia of Astronomy, and then it featured Joy Division’s debut album, and then it became every post-punk teenager washed out t-shirt.