This topic appear on hacker news a couple months ago. http://news.ycombinator.com/item?id=87471 http://news.ycombinator.com/item?id=87471 As the other guy say

This topic appear on hacker news a couple months ago. http://news.ycombinator.com/item?id=87471 http://news.ycombinator.com/item?id=87471 As the other guy says, there's no uneven distribution of material, but it self-rights due to the properties of its surface.