Space Invader for dual color printing. I've made it in four colors by changing the filament when half of the model has been printed. I really like the effect of the four colors to see the infill net (10%) before it has finish the piece.

Just add the two STLs to your software and chose a different extruder for each part. If you want to print the piece with four colors, change the filament halfway through the process.

Important! The piece is a little weak on the joint so don't twist it to hard.