My wife asked me to make the numbered squares to use in a cakewalk she was organizing at a VBS carnival. I had two days to pull it off and they had to be durable enough to be stepped, stomped and jumped on and survive to be used again in the future.
Here's how I did it.
Step 1: Break Down the Plywood
I used 1/2" thick plywood to make my squares. This was to make them somewhat durable so they could be reused. I was originally told they would be set on grass so I didn't want them too thin. They ended up being on concrete but they worked great at this thickness.
I bought a full sheet (4'x8') of 1/2" plywood and had them cut it into two 4'x4' halves at the store. Easier transport and I only needed half of it for this project. I made 16 squares out of 1/2 of the sheet.
I first used the table saw to cut the half sheet into 11" strips. You could also use a circular saw to make the same cuts or even a jigsaw if that's what you have. It made four 11" strips.
Step 2: Finish Cutting the Squares
I used a radial arm saw to cut the strips into 11" squares. You could still use the circular saw or jigsaw to accomplish the same task. Or even a cross-cut sled on the tablesaw. Whatever saw you have and are comfortable with should do exactly what you need.
Step 3: Add a Chamfer (bevel) to the Edge
I used a router table with a chamfer bit to bevel the edge. There are many ways to accomplish this. You can use a hand plane, belt sander, orbital sander (although consistency is more difficult), or even just good old sandpaper and elbow grease. This step is completely optional but it softens the edge of the wood so it is not sharp. If you choose not to add the bevel I would at least sand the sharp edges to break them down and soften them.
Step 4: Sand...
I used a benchtop belt sander to sand all the surfaces and edges of the squares. This could be done with any electric sander or just sandpaper and elbow grease again. Knowing these are going to be walked and jumped on, I was not striving for furniture quality perfection but just smooth enough to not give splinters and for the masking tape to be able to create a decent line for painting later.
Step 5: Under Coating
I wanted the edges to be white and the numbers in the middle to be white. So I laid them all out and sprayed the edges and middle with a good coat of white paint. Let that dry completely before moving on to the next step. That's pretty important.
Step 6: Tape the Edges
I used 1" blue masking tape and started where the top of the bevel started and laid the bottom edge of my tape along that line. The tape folded up over the edge and that's where I chose to have my white frame line.
Step 7: Finish Taping the Edge
I added another piece of tape to finish covering the bottom part of the edge. I did both taping steps on all edges of all 16 squares.
Step 8: Prep the Vinyl
I used 3" vinyl numbers for the mask in the middle of the squares. To make the numbers easier to remove from the sheet, I removed the negative space (between the numbers) first. That makes getting to and removing the numbers much easier and quicker.
Step 9: Find the Center
Use a straight edge and lay it across diagonally from corner to corner and draw a small line in the center. Lay it on the opposite corners and draw a line that way. It should make an X in the middle and that is the center of your square.
Step 10: Apply Vinyl Number
Using the X you can sort of eyeball where to place the number(s) to be in the center. Make sure your numbers and all the taped edges are securely stuck without wrinkles so you can get a good line with the paint.
Step 11: Paint
I employed the help of my favorite helpers to spray paint all the squares. We had four colors going to match the theme of the carnival booth. Since we had a very short time, we used one pretty heavy coat. If we had more time I probably would have used two coats for best results.
Step 12: Remove Masking
Once the paint is dry enough, remove the masking tape and vinyl numbers and smile because it looks so nice.
Step 13: Finishing Up
If your are planning to use these on concrete I would suggest adding some sort of non-slip something to the back to keep it from sliding. It wasn't terrible but I did notice that when kids jumped from one to the next (which they will do) the squares did slide a little. I would hate for someone to slip and tumble on the concrete.
After two hours of use, they showed a little wear but nothing that can't be wiped up with a damp cloth and be ready for next time. We gave away 40+ cakes in that time. Loads of fun.
Thanks and good luck.