The Birdcage, an artful custom that utilizes BMW's new big boxer engine purported to be 1,800 cc (BMW will not confirm this yet) was designed and built by Alan Stulberg with his team at Revival Cycles Austin. It was their intent to have an open design so the powerplant can be seen from every angle. The Handbuilt Show. Austin, Texas USA. Friday, April 12, 2019. Photography ©2019 Michael Lichter.