You can wire one resistor + led to each digital port 0 to 11. In AVR you can turn one complete port (8-bits) at once but I don't know if that is possible in Arduino... I think DigitalWrite activates one individual port at a time. You can try adding 12 consecutive DigitalWrite calls or within a for loop and see if there is any delay in the lighting sequence... it may even create some interesting effect if you do it from the center of the 12 leds to the edge, or from the edge to the center...