Things you'll need:
Posterboard (Black), or if you can get polypropelene sheets even better. ~$1
1 12x15" frosted cutting board (thin plastic, avaiable at most dollar stores)***
Scissors or olfa blade
Ruler & Protractor (not needed if you print out the template)
Electrical Tape (preferrably black)
Velcro with adhesive backing (or you can glue it yourself)
Optional: Glue, if you want to make tabs and glue it instead of using electrical tape
***If you can't find the clear frosted cutting board you can simply cut the same shape out of the posterboard then cut a small window in it and use tissue paper, velum, or even a cutout section of a white plastic bag.
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Step 1: Supplies
Step 2: Print The Templates Then Trace Onto Posterboard
When printing these make sure you disable "fit to page", these are designed to fit on a standard 8.5" x 11" sheet. I suggest measuring the pieces after you print them to make sure they weren't changed. The templates should measure exactly the same as the dimensions labelled on them.
Trace the front panel diffuser onto the cutting board. It may be a good idea to make a few ticks to show you the line to fold along as well (template shows the fold lines).