This all a bit dull, but it could be duller. So how about attempt to do that. If you think this is an anatomical fact about blueberries, it is not. That hole disc is round.

The calyx, which consists of sepals attached to the fruit give it the look of the torx shape in some cases. This is simply due to it having five united sepals that are reminiscent of a star shape themselves. The sepals are modified leaves that protect the flower bud during development which are fused to blueberry fruits but I digress.

The scar from the calyx, which is the disc in the middle where the actual flower petals, nectory, and sexy bits once were connected is round.