Around 2003, Dupuis Publishing was looking for a team to take over Spirou & Fantasio from Tome & Janry, and Vehlmann was shortlisted as the new writer. He wrote a short script for different artists to try their hand at, including Yoann and Clarke (Melusine). However, the job ultimately went to Morvan & Munuera, and years later Clarke put the pages up on his blog.
According to Clarke the pages were also colored, but he doesn’t have them, so we’ll make do with the black and white:
Yoann’s version has also been published, in the special edition of Les géants pétrifiés (“The Petrified Giants”), and there’s a scanlation by Miriam here.
Clarke also made this page (posted here), where Uncle Paul discusses the technical aspects of the machine: