Because my Prusa i3Mk3S+ isn't a 300x300 printer I resized (80%) Props3DPro‘s models on Thingiverse so they would fit my printer. The arrow sign works perfectly with Mario Kart Live, however the altered size changes the perspective a little bit. So be aware that you have to figure out when to steer exactly in regards to the original Mario Kart Live Arrow Signs.
The original model came from https://www.thingiverse.com/thing:4697220. It's created by Props3DPro from Vancouver, Canada (https://www.thingiverse.com/Props3DPro).
The author remixed this model.