I have a vintage fire department, station alerting box that was used to notify fire trucks that they were being dispatched on an emergency. The box is slightly larger than a shoe box and is divided into 4 sections, each with its own 12v light bulb. The bulb would illuminate thru a translucent cover on the box and identify the individual fire truck or trucks being dispatched. I would like to build a curcuit that would randomly illuminate one or more of these bulbs for 30 seconds then turn off and do it throught the day when its turned on. This would simulate apparatus dispatch for the display. A "random light generator circuit" that just flashes lights wont work, it needs to operate 3 or 4 different lights in different order for upto 30 seconds. Thank you for your help.