what do you think is the best and easiest way to describe the relativity of simultaneity? The best possibilities I'm aware of are:

a) The one of Comstock (1910), who uses two platforms. On one platform we have the endpoints A and B, and from the middle between them a signal is sent to both of them. Because of the constancy of light, the light rays will reach the points simultaneously and the clocks at A and B will start at the same time. However, from the point of view of the other platform, one ray arrives at first at A, while the second ray need longer to arrive at B, so the clocks are not synchronous.

http://en.wikisource.org/wiki/The_principle_of_relativity

b) And the one of Einstein (1916), who sent two light signals from A and B (the endpoints of a railway embankment and a moving train) to a point in the middle between A and B. If those signals arrive at the same time in the middle of the embankment M, then they started simultaneously in the frame where the railway embankment is at rest. However, the middle of the train M' is first hit by the signal from B. This is interpreted by an observer in the frame where the moving train is at rest that the signals were

**not**sent simultaneously.

http://en.wikisource.org/wiki/Relativity:_The_Special_and_General_Theory/Part_I

I find both ways interesting and intriguing, what do you think?

Regards,