Very simple, versatile modular design
No limits to the number of modules used in the ring Circuit diagram using LEDs:Circuit diagram using Lamps:

Parts:

R1 R3 R5 10K 1/4W Resistor
R2 R4 R6 470ohm 1/4W Resistor
C1 C2 C3 47uF 25V Electrolytic Capacitor
Q1 Q2 Q3 9013 NPN Transistor
Nine pcs led 20mA 3V

The purpose of this circuit was to create a ring in which LEDs or Lamps illuminate sequentially. Its main feature is a high versatility: you can build a loop containing any number of LEDs or Lamps, as each illuminating device has its own small circuit. The diagrams show three-stage circuits for simplicity: you can add an three number of stages (shown in dashed boxes NOTE: Series Multi-level will can’t work), provided the last stage output was returned to the first stage input, as shown.