In Phun you can create your own world of things that collide, bounce, swing, run, drive, fly and flow. To get started you can go to the File/Load scene menu and load some examples to play with. Don't be afraid to play around, anything you do can be undone by pressing the undo button or control-z.

You can select objects by clicking them. You can then drag the selected objects. To select several things at once, encircle them with the polygon tool or the box tool.

Erase objects by drawing a straight line over them with the polygon tool, or just select them and press delete.
