Many musical instruments which have a key for each note lay them out in this standard way: the piano, harpsichord, clavichord, organ, synthesizer, celesta, and carillon keyboards. Also, instruments such as the xylophone which have a separate sounding part for each note lay them out in this pattern.
The twelve notes of the Western musical scale are laid out with the lowest note on the left; the seven larger keys (for the "natural" notes of the C major scale: C, D, E, F, G, A, B) jut forward, with the sharp and flat keys less prominent. The pattern then repeats at the interval of an octave. Early harpsichord and organ keyboards have a range around 50 notes; the modern piano has 88. The standardization of white natural keys and black sharp keys began in England in the 18th century.
Non-standard musical keyboards