Call me silly but I have a fascination with mixed-use (or interfaith) religious architecture with a particular period (post-WWII it seems) feature: turntable altars.
This interest was fostered by its odd, gee-wizz, and even its kitch character, but the original inquiry came out of some thought around the appropriate interworking of worship in governmental settings, like military, aviation, or educational settings. Most of the turntable altars are and were found in military chapels. If you have one chapel, out of necessity it must serve the whole religious program. Here comes technology to the rescue.
Imagine a triangular tower that pivots on its vertical axis where each of the three sides are set for Catholic, Protestant, or Jewish worship. Pivot, and voila the building changes function. Simple chancel furnishings complete the scene.
No great thoughts here -- just a couple of pictures. Of course, the best pictures are "in-between" shots. (Coming from US government sites, I'm assuming they're public domain.)
And a remote link: