Help Needed

Hi All,
I was wanting to create a light box that my dad built for me when I was about 5. It had som small lights in it that was connected to a couple of 9 volt batteries. All it did was blink in a random pattern. It did this for at least 20 years before all of the lights went out. I was telling my son about this and he thought it was cool. Could some one help me with the parts needed and how everything will need to be connected sot hat maybe I can build one for my son.
He said he thought that if there was 3 rows of six lights with the top and bottem blinking going one way and then the middle row blinking going the other was would be cool.

Can some one help me with this. I would greatly appreciate it.

Thanks
Ken