Flash-Applications and Java-Applets
Adam Trepczynski allowed me to integrate his Shockwave-animations in my pages. They present the Epstein type of space-time diagrams (with or without gravitation !) in a flat and in a rolled version. A small mass is moving in one spatial dimension through the center of a massive object as disussed in part H5 of my book. You can leave the animations with a click on the button "one page back" in your browser.
Franz Embacher and Petra Oberhuemer have worked out a Java-Applet demonstrating STR with space-time diagrams of the Minkowski type. The infinitely extended x-t-coordinate plain of Minkowski can be mapped on a finite square according to Carter and Penrose.
The pages of Franz Embacher (University of Vienna) are a rich source of material in the field of STR and GTR.