1. Piece of 2x4 or 2x3
2. Wood shims
3. Wood glue
4. 1/2 nails (optional)
Step 1: Glue Wood Shims
2. Create 2 strips with 4 shims.
3. Glue the 2 strips across the top of and perpendicular to the 2x4. These will be the base strips.
Step 2: Add Additional Cross Strips
2. Optionally, reinforce the attachments with 1/2 inch nails.
3. Continue to build up the walls to about 5 or 6 inches high
Step 3: Fill in Gaps
2. Glue smaller pieces of wood on the bottom to fill the gaps in.
3. Paint the box to make it look clean.