Each of the four panels has time, the unifying thread. One static graph also has how up, another how left, a third how far away the events were/will be. The dynamic graph integrates all that information.
There are eight boundaries: past and future, up and down, left and right, near and infinitely far. All events that appear in the four graphs must be withing these eight constraints.
sweetser@alum.mit.edu copyright 2003, all rights reserved.
