Pace car lights

Anybody got the schematic :?:

The idea is to have 2 strobes which alternately (left-right) flashes two to three flashes.

I can manage to alternate the flashes, but i need the schematic for strobe unit which runs on 12V and fires 2 or 3 flashes in sequel, than stops.

well make 2 strobe units.. then wire up a relay that can switch the 12 volts between the 2. then, all you need is somethign to creat a pulse every 3 secconds? somethig to that ewffect... i think a 555 timer with a big enough capacitor and resistors can dot that