Ah, a big ball bouncing around the screen. Although a bit of a cliché, it's one of my favorite demos. It manages a large area of full resolution graphics without any flicker or other compromises.
The demo only works on a TRS-80 Model III.
There is a now a version that will work on a slightly modifed Model I. It is included as ballm1.cas and requires Tim Halloran's VBLANK mod. Or you can run it under trs80gp like with trs80gp -m1 -m1_vblank ballm1.cas
InstructionsPress keys 1 though 7 to speed up the ball's motion. 1 makes it go a bit faster, 7 a lot faster. And holding all of them down will make it go at top speed.
George Phillips, July 3, 2009. george -at- 48k.ca