There are two pieces: Car Park and Car Park Roof. They are interlocking and stackable vertically and horizontally. It features indents for most wheel dimensions and a curb to prevent any cars from rolling off. Please leave feedback if you do print it.

Assembly instruction:

1. Print the desired amount of car_park1. DO NOT PRINT SUPPORTS IN THE HOLES ON THE BOTTOM; THEY ARE DESIGNED TO PRINT SUPPORTLESS.
2. Remove supports (supports are probably optional, but I haven't tested it).
3. Connect Horizontally first.
4. Add another layer.
5. Repeat steps 3 &4 until satisfied.
6. (Optional) Top off with car_park_roof1

WARNING: SOME PARTS ARE FRAGILE