The Mercedes Monoblade was my favorite design, although it was notoriously expensive and unreliable.
https://99percentinvisible.org/article/behind-screens-windsh...
https://99percentinvisible.org/article/behind-screens-windsh...
Today, my MB uses two wipers, but it is nevertheless an interesting design as well. Windshield cleaner fluid is not sprayed out though jets that roughly cover the windshield; instead the cleaner fluid comes out from the blades themselves as they move across the windshield. This is almost not visible while it is happening, while cleaning the windshield just as well or better without vision obscuring spraying.
My family were a Citroen (hydropneumatic suspension ftw) family growing up, so we had a variety of 'monobladed' cars, the wipers weren't one of the unreliable parts.
* Photos and diagrams here: http://www.spannerhead.com/2012/11/28/technical-curiosities-...
* A slow-motion video of the wiper in action here: https://www.youtube.com/watch?v=KHtEAMwcWI4
* And a couple visualizations of how it works mechanically: https://www.youtube.com/watch?v=_quBiMLqNoc, https://www.youtube.com/watch?v=LdNu113Ep2U