LED T-Shirt Project

Hi there, I am currently undergoing a project of making a LED T-shirt for my school. I basically have 3 rainbowduino and wanted to combined all three connecting the VCC and GND. I tried to on it with a power supply but only the rainbowduino that is closest connected to the power supply is on while the other two did not activate at all. Is there any method or anyway that I can troubleshoot this problem? I need help urgently =(

From the pic its clear you've only connected SDA SCL and GND. The second Rainbowduino is not getting power. Read the markings on the board by the headers to see the signal names.

You should send power through the screw terminals, using short piece of copper wire to bridge these between modules, the vcc on the smaller headers doesn't handle high current.

Thanks alot =) Do i have to connect all 4 Vcc and Gnd of the terminal?