A handful of small gems, though, have emerged from Microsoft's Windows Store store, includuding one particular standout: Fresh Paint.
Source: CNN Money
On the surface, Fresh Paint is a straightforward finger-painting app that lets users "draw" on the screen with four different brushes and a color palette. Once you start to play around, though, it becomes clear that this is much more than an updated MS Paint. Fresh Paint actually makes your "brushstrokes" appear as though you're painting with oil on a textured canvas. That level of detail took some serious feats of science and engineering.
Fresh Paint's origins are in Microsoft Research, where five computer scientists worked several years ago on giving PCs the ability to simulate complex brushstrokes. Painting involves a significant amount of physics: just imagine how thousands of bristles, liquid paint and a rough-surfaced canvas interact. The team needed to create complex algorithms to match each touch and gesture on the screen to real-life paint.