Yes sorry :)
A & B are two points in space. 1, 2 & 3 are events on the vertical line that represents time. The jumble of lines between the events is a way to show when A sees event X relative to when event X actually happened at point B.
This actually started out quite simply, with two vertical lines and a diagonal line between them but as I started thinking about it more I needed to add more lines and its gotten to the point that perhaps I'm the only person that understands my jumbled diagram :)
Take event 1 for example. It happens at the same TIME for both A and B(same spot on the verticle lines). The first horizontal line represents when both points SEE the others' event in SPACETIME.
Also, if you imagine the dialonal lines as more of a spiral and assume the points are the Earth and the Sun you can begin to see the following...
1) Everything travels through time in a strait line.
2) Spacetime is curved and is why bodies appear to go around eachother.
LogicaLunatic