Earlier this year, I did a bit of technical work for an artist, Kerry Tribe, on her installation/film project called H.M. It was a remarkable piece. At its core, it was a documentary about a man who had some experimental neurosurgery that left him with an active memory of 20 seconds. What made the piece so remarkable was that it played back on two 16mm projectors, the film being delayed by exactly 20 seconds from one to the other. The film was shot in such a way that the two projections, displaced in time by 20 seconds, worked together uncannily well, sometimes displaying complementary images, and even, in one visually notable part, forming a complete image that spanned over the two screens. It's pretty great.