Another option would to be to use real glass cut in 5" X 5" sheets and use glass etching creme with stencils. I have a CNC machine which I used to make an etched version and it shows up a little better.
The reason the box is made from two pieces is because the slit is shorter on the bottom to give the acrylic a ledge to sit on. It is critical the slit in the top and bottom line up when you glue the pieces together.
If you cut the slit accurately enough the acrylic will fit snugly and can be replaced with different designs. I include 5 designs in the pattern book.
The green tint in the is because the acrylic I used did have a green tint.
Don't let that put you off because the scroll saw version looks really good also. If you are good with pattern making these would make great personalized gifts.
Below is a picture of the 3 pack of puck lights I used for the project.
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