And in case anyone is new to Greg Egan, there's also the Orthogonal series (starting with The Clockwork Rocket) where the metric is (+,+,+,+) - the "time" dimen

And in case anyone is new to Greg Egan, there's also the Orthogonal series (starting with The Clockwork Rocket) where the metric is (+,+,+,+) - the "time" dimension is just like the spatial dimensions. Pretty cool read with a bit of physics background!