Explore the Atari Display Lists with this shape changing program.
Here's how it works.
LINE 10 - establishes a
standard display list for mode 7.
LINES 20 to 60 - draw a
LINE 100 - sets the pointer
to the display list.
LINES 150 to 250 - change the
display list a line at a time from the standard 4 colour mode with 96
vertical rows to a 4 colour mode with 192 vertical rows on a full
screen. This effectively halves the height of the circle producing an
Try changing LINE 150 to Z=-1, or Z=-2. or Z=-3.
Add more colours to the circle or change the original shape. You
could also try starting off in a different graphics mode but don't
forget to make LINE 10 specify the mode with the largest RAM requirement
that you are going to use.