This page contains an interactive applet, which will only be run if your browser supports the Java programming language.
Below is a spacetime diagram containing two “short” wormholes — that is, wormholes with negligible interior distances between their mouths. The two red vertical lines are the world lines for the mouths of one wormhole, and the two blue lines are the world lines for the mouths of the other.
Anything entering one of the wormhole mouths emerges “immediately” from the other, where “immediately” is defined in the reference frame of the wormhole in question.
By tilting either of the blue world lines (click on the line, then drag the rectangular handle that appears), you can change the relative velocity between the wormholes and observe the effect this has on the path of a sample photon (magenta) threading its way through both wormholes.