This is an optical illusion combining both a left pointing arrow illusion and a right pointing arrow illusion. Look at it from one side and the arrows point in towards the center of the disk. Look at it from the other side and the arrows point out away from the disk.
Tired of making decisions? Boy, are you in luck. There's a small hole in the center bottom of this thing so it can be spun on the included stand. Give it a spin and let it choose whether you'll stay in or go out. Should you invest in Google? Give it a spin and let it decide. Up for some poker with the guys? Stop stressing over those tough decisions and let the arrows determine your fate.
I've included the model with and without supports tear-away tabs. The supports tear-away tabs make support removal very easy. They're designed to be used with the supports interface feature of Cura or similar feature in other slicers. If you're not familiar with the support interface it's essentially a raft for the model that is placed on top of the supports, but instead of being flat like the raft it is contoured and shaped the same as the bottom surface of the model. It's an excellent feature, but if you set the support Z distance fairly small to get a smoother surface, it's almost impossible to remove the supports. These tabs extend the support interface out from the model and provide an area to grab onto to tear away the supports from the model. The tabs are on a 0.1 mm post, which positions them at the right height, but is too skinny to be printed.
I've also included a version of the model without the words "In" and "Out", both with and without the supports tear-away tabs.
The spinner base is optional as it spins just fine on it's own on any flat surface. The version of the illusion model with the "In" and "Out" words is off-balanced so it actually spins better without the spinner base. I haven't printed the version of the model without the words, so I don't know if it's balanced or not, but it should be. Update 2019-03-22: Added V2 of the spinner base which is flatter, so it works much better for the unbalanced model with the words.
The hole in the bottom will cause Cura to generate a tiny blob of support there which is not needed. I tried using Cura support blocker feature to prevent it, but it ended up exposing a bug in Cura 3.6.0 that caused the generated G-code to have the wrong nozzle temperature as well as to start heating the unused nozzle. So I couldn't use the support blocker feature, but it wasn't a big deal as it was easy enough to dig the blob out with the pointy end of a screw which I had handy.