I bet most of you know this puzzle, but actually (for me at least) this was pretty tricky to design. Fusion 360 being one of the most famous design softwares, I do hope that the original source file can help, but I've also given the usual STLs.
P.S. I've left a 0.3 mm clearance/tolerance gap, feel free to increase/decrease it in Fusion. I, personally, used a tighter gap as my printer is very well tuned, but the STL is a bigger gap to appeal to larger audiences. Again, you can change it in Fusion.
P.P.S. I'm 14. So... PLEASE GIVE EXTRA CREDIT XD