LOS ANGELES — Michelle Mason’s designs have always represented the antithesis of what the outside world thought of as L.A. style. But my, times have changed. This California girl by way of Korea has become a significant force in the downtown revival here. And at her show last weekend, held at her vast downtown gallery/atelier, she showed plenty of the cool looks now redefining the West Coast’s aesthetic. Here, her piped skirt and top cinched with a leather sash. For more on fashion week, see pages 4 and 5.