A black background can work if you're emulating a terminal. You probably don't want your whole presentation to look like this, though.

1. > Errno::ECONFUSED
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2. $~: make it work
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3. $~: make it work
$~: sudo !!
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4. $~: make it work
$~: sudo !!
$~: sudo !1!1!!!1!
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5. .
Finished in 0.00073 seconds
1 example, 0 failures
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6. .
#WIN
Finished in 0.00073 seconds
1 example, 0 failures
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