circuit is an attached file.

 

Looks like a typical transistor flip-flop.
Each transistor is alternately turned on off.
http://www.talkingelectronics.com/projects/5-Projects/Projects16.html
Max.

 

I was studied it about 40 years ago, time go so fast, it seems like as yesterday, please google : bjt astable multivibrator circuit.

 

Take a look here
http://forum.allaboutcircuits.com/threads/astable-multivibrator-how-does-it-work.32164/#post-200183