So, have the propellers mounted at an angle to each other? Sure, it'll still fly.
Normally, the propellers of a quadcopter all produce thrust in the same direction, and all of the thrust contributes to holding the quadcopter up (and to rolling and pitching it, depending on how fast the propellers are going relative to each other).
If you angle the propellers into a V or something, then the propellers will produce some thrust in concert with each other and some thrust in opposition to each other. So, part of the thrust will contribute to holding the quadcopter up, and part of the thrust will serve absolutely no purpose at all.
The result: the quadcopter will still fly, but it will waste some energy as it does. I'm not aware of any advantages to having the propellers angled like that.