Hey, let's not repeat yet.
Let's continue the pattern with
dark, light, med, light, dark
Then repeat....... cool, arrows


Look.... change the last two rows and
you get a diamond of dark ones


Switch the three middle rows and
you get an X of light ones
Now, exchange a few like you meant to do that....Nice
There, a "Random Pattern", by complete chance and in only 8 tries. :)
(Is "Random Pattern" an oxymoron?)