Step 1: What you'll need
- One sheet of paper-coated foam core board, 20" x 30" (see here for details)
- Exacto-knife and cutting board
- Long ruler
- Pencil and eraser
- Graph paper
- Black fine-tipped permanent marker
- Assortment of colored permanent markers
(for this project, I used red, light green and dark green for the piranha plant)
Step 2: Preparing the foam core
To scale the image larger on the foam core, you'll need to draw a grid, using the pencil and ruler, where each square will be larger than the ones in your reference drawing. For example, in my reference, I used a scale of 1 square = 0.5 cm, which I then doubled to 1 square = 1 cm on my foam core, creating a final product twice as large as the original. You can use this scale, or make your centerpieces even larger, though I found this height to be just high enough as to not hide your dinner companions from view. Draw your scaled grid onto both sides of the sheet of foam core.
With the aid of your reference drawing, transfer the outline of your image onto the foam core. You'll also want to transfer the outline of the base of your image, which in my case, is the green pipe. This crosspiece will act as the support which will allow the centerpiece to stand on its own, while still remaining 2D.
Step 3: Cutting out the forms
Next, begin cutting away sections that are not part of your final design. Foam core is a remarkably easy material to cut through, and 8-bit images are all straight lines, so this part is very easy-going. Remember to check the underside of the sheet to make sure your cuts go all the way into the corners before ripping the cutting away. This will make for much cleaner corners, and no rough bits hanging off the back of your centerpiece. Proceed the same way with the extra base section.
To make the crosspiece, stand the base section sideways on the center of the base of the main piece. Trace along both sides with your pencil. Reverse the pieces and do the same on the extra base piece. You're only going to cut half of this center notch out to be able to stand the two pieces together. On the main piece, cut out the bottom half of the notch. On the extra base piece, cut out the top half of the notch. Test the stand by sliding the two pieces together perpendicular to each other. Remove more from the notch if the fit is not right and test again.
Step 4: Adding color
Continue filling in the image using the paint-by-number technique with each subsequent color until your image is completely colored. One important note: if you are coloring in a section using a lighter, more transparent color, such as yellow or red, make sure to erase your pencil grid lines before you do so. Otherwise, you'll see the grid through the coloring.
Flip the piece over and color the second side in the same way. Color both sides of the extra base section as well.