Skulls in space

Thanks. It wasn't too hard, the stars have a vector magnitude which is multiplied by the (inverted) ship direction, to give them a velocity. It's a shame though, I've lost the source code for this and I forgot to upload it.

trying to understand the concept behind unbounded world. if you had a super-mario type of "landscape", and the viewport can see just a portion of the larger world, how to create the effect of moving the viewport about the larger world. the dimensions supplied to the World constructor for an unbounded world seem to define the dimensions of the view port. how to specify the bounds of the larger world?

Mark, there are no bounds for the larger world - that is what makes it unbounded. The dimensions supplied to the World constructor do indeed specify the viewport size; the difference between a bounded and an unbounded world is just that the position of the actors within a bounded world is constrained to be within the viewport. To create the effect of moving the viewport around, you need to move all the actors within (and figure out some way to move the background, if you are using one. The easiest way is to draw the background with actors, rather than use a background image). There should be a few examples of that here on the greenfoot.org website, try a search or post in the forum.

@mark.hayes If you want the world to have a limited size, look at this scenario: http://www.greenfoot.org/scenarios/5806 This also contains the scrolling background.