For our readers (and young engineers) we have created an animated bookmark. As you tip it, the wheels go round, the piston moves back and forwards and even the valve gear moves as it should! The moving image was obtained by taking lots of pictures of Fiery Fox, with the motion set in different positions. Then some wizardry on the computer and it moves remarkably realistically!
Bookmark is 150mm long by 50 mm wide plus tassle.