Window bars that curve outward at the bottom rather than running straight down are known as "potbelly" grilles (also called "window belly bars"). The design is functional, not decorative — and it solves a real space problem that flat security bars create. Security First, Always Window bars have been used for centuries as a physical barrier against unauthorized entry, and … [Read more...] about If You Notice Window Bars That Curve Outward at the Bottom — Here’s What They’re Really For