Sorry folks, there isn't a lot of documentation, because I don't
intend to ask for any money for this program. So I'm just including
some pointers.

Depending on how fast (or slow) your machine is, you will probably want
to use the recording feature. This saves only the integer X/Y screen
locations of the wire frame that makes up the crane to disk which can
then be rapidly loaded and displayed during playback.

The best method to use the Record feature is to start the recorder
going before starting the animation with Animate. Then when you want
to stop recording stop the animation first, then stop the recording.
Then you can use the playback feature. If you want to use this
program extensively you may want to add features like named recording
files, and self-looping.

It should be fairly easy to extend the code to animate other three
dimensional objects by loading their point lists from a disk file.

The way I cause movement is that I create a virtual point that is in
"front" of the crane that also undergoes rotations. (All of the
crane points are centered around (0,0,0).) Then I apply the
offsets generated to the three dimensional location point I keep
lying around. Finally I add the location point to the rotated crane
points. I repeat this for each "frame" of movement.

Enjoy!

Mike