WORKING:
The working of the circuit is based on charging and discharging action of capacitors. When one capacitor is charging current flows to base of alternate transistor making emitter collector path conductive and making the Led on that side to light up. When capacitor is charged, it stops conducting and switches OFF conduction transistor. And then the other capacitor begins to charge switching ON the other transistor. At the same time other capacitor discharges and this cycle repeats.