PSR B1919+21 is a pulsar with a period of 1.3373 seconds, and a pulse width of 0.04 second. It was the first radio pulsar discovered (on November 28, 1967 by Jocelyn Bell Burnell and Antony Hewish). The power and regularity of the signals was thought to resemble a beacon, so for a time the source was nicknamed "LGM-1" (for "Little Green Men"). An image of the radio pulses was later used by Peter Saville in 1979 as the iconic cover art for Joy Division's Unknown Pleasures LP. This gist (unfinished) is an attempt to animate a trace over the signal - there appears to be some corruption in the data points that needs correcting however.