Draw a vertical rectangle measuring 2 inches wide and 8 inches long.
Divide the rectangle into four equal 2-inch squares.
Draw a 2-inch square on the left side of the second square from the top of the rectangle, sharing a common side. Repeat on the other side of the same portion of the rectangle.
Draw a 2-inch by 1/2-inch rectangle adjoining the bottom square of the rectangle and the left side square.
Score all the lines lightly with a pencil or a bone folder.
Cut around the outline of the T-shape made from the squares.
Fold on the scored lines.
Add glue to the 1/2-inch flaps and tuck them inside the cube to hold it together. You may want to add a tiny piece of tape on the outside. Remove the tape once the glue dries.