How GIFs work
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Now look at the German flag.

It has three horizontal stripes, black, red and yellow.

So the code for a 15-by-6 German flag would be:

BBBBBBBBBBBBBBB
BBBBBBBBBBBBBBB
BBBBBBBBBBBBBBB
RRRRRRRRRRRRRRR
RRRRRRRRRRRRRRR
RRRRRRRRRRRRRRR
YYYYYYYYYYYYYYY
YYYYYYYYYYYYYYY
YYYYYYYYYYYYYYY

which could be abbreviated:

R15
R15
R15
B15
B15
B15
Y15
Y15
Y15
which is smaller -- images with horizontal lines of colour abbreviate better than with vertical ones. The French flag has to change colours three times every line but the German flag doesn't.
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