Morrison's radioglyph scheme
Morrison's radioglyph scheme was an elaboration, by Philip Morrison, of Hogben's early radioglyph scheme, Astraglossa, for communicating with extraterrestrials.1 In Morrison's version, numbers are represented by square-shaped pulses (e.g. five square pulses for the numeral 5), and mathematical operations such as "plus", "minus", "the reciprocal of", and so on, by other pulse shapes. Distant beings would be instructed in the meaning of these symbols through simple arithmetic. Next, pi (the ratio of the circumference to the diameter of a circle) would be introduced as the sum of an indefinite series of fractions. Morrison would then send a series of extended radio signals, each marked at its start and finish by a pulse, with occasional pulses in between. These he would intersperse with the symbol for π in the hope that the recipients would catch his intent; namely, that the lines of radio emission should be aligned, one below the other, so that the seemingly random pulses form a circle. This would establish the raster, or pattern of horizontal scanning lines, of a television screen which could subsequently be used for more elaborate communications. See also CETI.
1, Morrison, P. "Interstellar Communication." Bulletin of the Philosophical Society of Washington, 16, 78 (1962). Reprinted in A. G. W. Cameron, ed., Interstellar Communication.