Trace out rough outlines of the legs on top of the box.

The front legs will be made from three pieces of cardboard glued together. The back legs can be made from a simple U-shaped piece of cardboard. 

Cut out a big square around the legs you've outlined using scissors or an X-acto knife.

Once you've extracted the top piece of cardboard, follow the lines to cut out the leg parts.

Add a line of hot glue about 1/8" from the edge.

Squash leg into the middle of the line of hot glue.

Hold it in place for about 30 seconds, being careful to keep it at 90 degrees!

Add a thin line of hot glue along each edge to provide more support. Do the same for the other side.

Now we'll add a popsicle stick to strengthen the leg. You may also use a thin piece of wood or some stiff cardboard.

Make a line of hot glue along one outside edge of the cardboard. Press popsicle stick down.

Use hot glue or double sided tape to fasten servo hub to the top of the leg assembly.

Mark the center point where the servo hub will attach

Use hot glue to add a popsicle stick (or bamboo skewer or similar). This will strengthen the cardboard leg.

Use double sided tape to stick the servo hub to the finished leg.