YOU WILL NEED:

DC electric motor (commonly found in dollar store fans) x1

3v battery pack (also commonly found in dollar store fans) x1

AA batteries x2

Alligator clips x2

3D printer (at least 1) 

TPU

Kabab Skewers x2

Whatever hard filament you want


ASSEMBLY INSTRUCTIONS:

Once you have printed all parts, lay them out. At the front of your box mark a point roughly 10mm from the front and 6mm from the bottom with a marker. At the rear mark a point 30mm from the back and 20mm from the bottom. Do the same for the other side. Once you have marked the points, at the front carefully poke a hole through the box with your skewer. This will become your axle. Attach the front wheels with the nipple facing in. Try to leave a little bit of play for minimal friction. At the back, poke the skewer through on one side and take it out. on the other side do the same. Now push the skewer through one hole but not the other. Take the LARGE gear and thread it onto the axle towards one side. Now you can fully thread it though the other side and attach the rear wheels similarly to the front. Glue your electric motor to the mount near the output shaft and fit the gear. Glue the motor to the bottom of the box making sure it meshes with the large gear (if you haven't already, make sure the large gear is NOT at the center but off to one side). attach the treads to the wheels and glue in the battery pack. Finally, attach the alligator clips and let it rip! (if the motor spins backwards, swap the wires)