Italian Ambulance Siren - please help.

How to make ambulance siren like this:

YouTube - Annoying Italian Ambulance Siren

Any idea??? Please help.

using a pic for the timing to control a bitonal oscilator ?

I much prefer the British ambulance sirens, they're easier to make with the good old NE556 too.

I think the idea of the italian siren is to be more startling which you would need with dumb careless iti drivers just to make them aware that an ambulance is on the way, and yes I lived there so speak from experience !, but then can say the same for UK drivers