[Noisebridge-discuss] Duplicating another area of the screen in osx?

[Sai Emrys]

I'm having trouble googling this, so maybe one of you knows an app
that does this...

For my 26c3 talk, I want to be able to
a) run the presentation in dual-monitor mode, so that I can see my
notes on my laptop
b) switch spaces to a textpad, so I can easily type for everyone to
see, but see it on my laptop screen (as if it was in mirrored mode),
so I don't have to look at the projected screen

... and do that back and forth fairly quickly.

The simplest way I can think of to handle this would be an app that I
keep on the laptop window of one space, whose sole job is to duplicate
the output of the 2nd monitor on that space - i.e. an app that just
mirrors a given chunk of screen.

Do any of you know something that does this?

Thanks,
Sai