If you see window grills with a curve at the bottom here’s what it means

Have you ever passed by a house and noticed that some window bars curve outward at the bottom, almost like a rounded belly pushing away from the glass? At first glance, they might seem like a quirky design detail or just an unusual decorative choice — but those curved bars, often known as “potbellied” window grills, actually have a very practical purpose.

For generations, window bars have been used as a simple but effective way to improve security, helping protect homes while still allowing windows to stay open for fresh air and ventilation. That was their original purpose. But over time, this clever design evolved into something that offered more than just protection.

So the question is — why the outward curve?