So the working design , I've got a very quick presentation on this , so um I've  oh no , you can't see a thing.  Oh well , I'm gonna draw it on the board then. It's in blue uh , and I couldn't change it.
Oh.
Ah.
We it's fine on my screen , but never mind. So um  the idea is that we've got the energy source um , which in our case will pr , oh well  okay , never mind. So um I think maybe uh two batteries , I dunno what they're called  six , or something like that.