Did Sigma design the Olympus M.Zuiko 75mm F1.8?

It's an open secret that many compact cameras are produced by OEMs - companies that produce large numbers of products that are then sold under other brand names. There are also consumer-grade zooms from big name manufacturers that look much alike (we know for a fact that third-party makers commonly create lenses for the bigger brands). But we were still surprised to read about Sigma's latest patent for a 75mm F1.8 prime lens...