American forces fitted some vehicles with extra wheels that protrude from the front (explosions ahead of a vehicle are less destructive than underneath it).
Upon inflation the ballonets protrude through the ring meshing to form occluded dimples the method permitting a large volume of gas in a smaller disc shaped area.
So before you allow a challenge to cause your lower lip to protrude, remember that our most creative work is often forged in the crucible of tough times.
The system also has more or less the same book-inspired shape as Lenovo's U-series Ultrabooks, meaning when the notebook is closed, the top and bottom edges protrude ever so slightly beyond the sides, sort of like a hardcover shell cradling a spine full of pages.