Back to parabolas...

Remember the parabolas we saw before? In bridges... and paths of projectiles like when you throw a ball in the air.

They have cool reflective properties too.

Check it out:

This is why paraboloids are used as satellite dishes and as the mirrors in telescopes.

And check out these flood lights:

Can you see from the reflective properties who paraboloids would make great flood lights? (Compare this to the ellipsoidal spot lights.)