Step 2: Glue the cubes together
Drill a hole in each cube - I used a drill bit with a diameter of 3mm (0.1 inch) and drilled 1 inch deep.
Put the drill bit in one of the holes, the bit will serve you as axis.
Put wood-glue ON THE MARGINS of the smooth surface of one cube.
Put the other cube on the axis.
Glue the two cubes together and press them with a clamp.
Let it dry.