This cooling bowl tries to determine where a part cooling fan has deficits. The bowl has corners to further make it difficult to print it. The corners are stress points that like to curl..
The bowl shows if your part cooling fan has even cooling all around (360°).

The maximum angle is 65°, because when printing with a 0.4 nozzle at 0.2 mm layer heights the outer perimeter just barely touches the layer below it.
Printing at 0.1 mm layer heights will make it easier to print this model .