In general, the regions of expanding warming upwelling water in the Indian Ocean, North Pacific, or wherever they are, must create slight bulges in the surface, and the regions of shrinking, cooling, sinking water in the Arctic must create slight depressions in the sea surface (again, I mean in a very low pass sense — obviously storms, tides, etc, create all kinds of short - terms signals obscuring this). (realclimate.org)
If you run your fingers down the case you can, in fact, feel a very slight bulge, but the bulge isn't visible and doesn't appear to have in anyway distorted the plastic or created any points where the back doesn't firmly connect with the body of the phone. (howtogeek.com)
Even the untrained observer can spot the flaws, and slight bulges here and there can ruin a work of art. (religion-online.org)