They will determine whether certain objects or pictures display line symmetry, and the number of lines of symmetry in those objects or pictures. (gigglelearn.com)
Some are placed in the corners while others suggest a kind of symmetry as they are placed vertically or horizontally in the middle. (brooklynrail.org)
It adds a sense of symmetry between the front and back of the phone, but also helps give the phone that edge - to - edge screen appearance. (pocket-lint.com)