There are border-radiuses, then there are squircles. Squircles are puffed out edges + rounded corners. What you're talking about here are corner radiuses (border-radius in CSS). The design by Amjad in your article seems to be using squircles, but the rest are just rounded corners on flat-side rectangles. The former is much harder to do (especially in code) than the latter, and the latter is nothing new. With your header image, I was hoping to see some kind of new trend with 3d looking shapes mixing with something else, but alas...