The main source of inspiration for "Chats gris" remains the artist's three cats, which roam his studio. Patrick Gourgouillat, a cat lover, has attempted to represent the feline enigma. To do so, he used other sources of inspiration, such as the Prague Astronomical Clock and a short novel by French inventor and poet Charles Cros. The colors used are blue, orange and gray, all of which have strong symbolic values. In Eastern cultures, gray cats are a symbol of good fortune... For the moon, Patrick Gourgouillat has painted a QR code in a circle. A writing as mysterious as a hieroglyph.