The Assassin’s Teapot Is A Mischevious Design
Excellent vidéo explicative (j'ai aussi trouvé un model 3D)

Many films use a similar trope when it comes to poisoning. The aspiring murderer ingests a drink poured from the same vessel as that given to their intended victim to indicate the liquid is safe to imbibe. The Assassin’s Teapot is a way one could achieve such a ruse, allowing two different liquids to be poured from what is seemingly a regular teapot, as shown by [Steve Mould].
via Hackaday : lire l’article source