Third place went to "Silhouette Zoetrope." It's fairly familiar looking if you've seen an old zoetrope, but this illusion has a unique twist. The images that are normally inside the zoetrope creating the illusion of movement are moved to the outside.
Zoetropes create apparent motion when a series of similar images pass in rapid succession. Much like early animation, our brain fills in the gaps. "When the Silhouette Zoetrope is rotated, the slots strobe behind the cutout images, animating them apparently inside the empty slotted cylinder, which creates the illusion of moving silhouettes placed into space," write the judges.