Coldplay cover: That was easy.
Guest Design Observer Adrian Shaughnessy does the heavy lifting in his Decoding Coldplay’s X&Y. Spoiler ALERT!!:
"...Du Sautoy proceeds to decode the symbol. He identifies it as an example of a system devised in 1870 by Emile Baudot for telegraphists, where each letter of the alphabet is represented by a series of five 0s or 1s. The letter X, for example, is represented by 10111, and Y by 10101. Referring to the Coldplay graphic, he states: “The first column of colours on the cover shows a black and grey block representing a 1, followed by a gap representing a zero, then three more blocks of colour giving three 1s. The first letter in Coldplay’s title is the letter X. The last column gives us 10101 or the letter Y."