What does the corner of Apple's mobile phone mean?

According to official website, Apple's mobile phone, the stacking angle of Apple's mobile phone means that the angle of the mobile phone is messy and the shooting angle is not fixed. The specific performance is that the tilt or jitter is too large when taking pictures. This practice will lead to unstable picture and blurred picture. When taking pictures, you should fix your mobile phone and choose a suitable angle to avoid the formation of corners.