This is a standard 20mm calibration cube, but with two colors so you can calibrate your dual extruder set up! In my picture you can see I printed two of them, at 90 degree angles with the colors switched. This was to check differences in x-y alignment, and test stringing since my new set up is bowden fed. That's about all there is to it. Have fun!
The sections of color on each layer are so small that this will be a solid cube of plastic (infill doesn't matter) with most 3D printers and most stock settings.
Designed in Fusion 360. Sliced in Slic3r.