To get the T-Rex jumping, press the up arrow, to get it lower, down arrow. There are many obstacles to be avoided: You'll face a lot of cactuses - to jump them over you can press up arrow - and after thirty seconds, pterodactyls will arrive, so you'll have to lower T-rex by pressing the down arrow key. After sixty seconds the stegosaurs will arrive, and even those must be skipped. After ninety come gallimimis, which run at great speed and you must have a ready hand to jump them over. The clouds, the holes and the grain of the ground are scenic elements and should not be skipped. The variable marks the steps.
