Fans appear on the upper left platform, its a bit small but you can probably at least see the fans as they are spinning. You have to pick them up and drop them on the lower platform marked delivery. The game finishes after you stack 7 of them on top of the lower platform.
We are planning on expanding on the concept and adding some more minigames in the future and I might edit the sprites for the fan platforms to have them stand out a bit from the background.