Commodore VIC-20 User Manual page 45

When you have typed these lines, look them over and see if
they match what is shown on this page. If there are some that
don't match, retype those lines from the beginning. Use
the
to move back to any lines you want to retype.
Once you are satisfied that the lines are all right, get a piece
of paper and a pen or pencil and place it nearby. Then type:
[R] [U] HI and Press
Your screen should begin to blush and flash. The border
changes colors. The background changes colors. Even the
small message at the top of the screen is changing colors.
The VIC Is displaying 255 different color combinations.
(Syntax error in one of the lines? Retype that line and
then type:
and again.)
While the VIC is running, if you notice a particular set of
colors that look interesting; write down the number of that
combination. Only the number at the end of the printed
message is changing. The "POKE 36879," stays the same.
(Occasionally, you will not be able to read the message
because it is the same color as the background. C'est la vie.
The letters and numbers will reappear after a few additional
flashes,) The VIC has eight border colors, sixteen
background colors, and eight character colors. You can put
characters in all eight colors over any background. That
gives you a lot of combinations to explore.
If you want to restore the screen to its original colors, simply
hold down the M3 key and hit
Line two in the example above is responsible for making the
VIC change colors. The line contains a POKE command.
Every POKE command has two numeric values that the
VIC uses:
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