Actors' strange behavior - getting closer to each other (when they shouldn't)- how to address?

mhedges

Hello -

While trying to emulate the behavior of Space Invaders aliens, I noticed that the actors get closer to each other when they reach the end of the right side of the play area and drop a line. The actors start out to the right; I believe the behavior happens the same on the left side if the actors start moving to the left side.

Is there a way to address this other than say, constraining a grid of characters to the position of a leftmost or rightmost actor? Constraining a grid of, say, 28 to 32 or more actors would probably hurt performance.

Attached is the unaltered sample file, if you wish to take a stab at this daily puzzle.

Thanks, regards.