Pause Function Enabled

To make it possible to engage in predictive lessons, a pause function has been implemented.  Now the spacebar instead of firing a bullet will pause and unpause the demo.  In the paused state, the trail and the vectors remain visible, but all dynamics stops.  The keyboard shortcut instructions have also been simplified and reduced in size to improve clarity and reduce on-screen clutter.

Please leave me a comment if there are any ways you feel this demo could be more useful in the classroom.