Sonny Day and Biddy Maroney are Australian illustrators, designers and artists operating a small design studio (WBYK). Their work is a conversation between two individuals played out in colour, shape, texture and drawing from their shared influences comic books, skateboarding, music and film. Sonny and Biddy worked and exhibited individually when they met in 2001.

They began combining their talents in 2006, creating screen-printed posters for Popfrenzy tours on their living room floor, and have been working as a team ever since. Today they work for clients big and small around the world. Since 2012 they have created many sold-out licensed film posters for Cinema / Pop-culture powerhouse Mondo, including two solo exhibitions in the company's Austin Texas gallery.

They've also had solo exhibitions in Monster Children, Mart and MTV Galleries in Sydney and Lamington Drive in Melbourne, as well as contributing to many group exhibitions across the globe. Sonny conducts kids (and occasionally adult) workshops, designing and painting skateboard graphics. He is also commissioned regularly to paint murals and exhibits in solo mode as often as he can.