You can connect the data lines from three different neopixel led strips to D10, D11 and D13.
I tried several neopixel ino programs, they all work fine but none of them accept multiple pin connections in one program.
The pin definition is set in the beginning of the program and then used in the void loop.
Defining more than one pin results in a "redefinition failure"
I hope you can solve this in your project....
I made a few diagrams for clarification of the connections:
(thanks Chris @chris101 for finding the GND & VCC pin information)
This diagram shows the connection of neopixel leds when the load is less than 1 Amp:
This diagram shows the connection of neopixel leds when the load is more than one Amp so a separate 5 Volt power supply is needed:
This diagram shows the connection to GND and VCC of the Littlebits system via a protobit instead of via the Arduino ICSP surface:
This video shows "running lights" on D10: