SACI's concept is simple but effective: he creates his drawings in advance, then goes out at nightfall with his sidekick, Caractère Spécial, to paste them in the streets of the Pink City. He reveals the location of the collage in a video and then invites his followers to search for it. This artistic treasure hunt is increasingly popular with Internet users.

For the process, Saci works on rolls of kraft paper, starting with a pencil sketch that he finalizes with a Posca pen, before cutting each piece with a cutter. He then uses a mixture of wallpaper paste and water, which he applies with a bucket and a roller. A quick, discreet, and artisanal method.