Two squares of black acetal ("Delrin™" except I think this is some generic brand) laser-cut in the chainring guard pattern.  The center area of the pattern is filled with circles of various sizes with a small center hole; these are spacersm used to get the right separation between guard and chain.

The square on the right is "empty", meaning the guard and spacers are removed and installed on a bicycle, the other is still in place and taped in place/together on its backside.

There's a blue Park Tools ruler across the top of the left square, showing that the square is 235mm (9-1/4 inches) wide.  (The ruler is legible because I used white-out to fill all the little recessed measurement lines and lettering, then wiped off the excess.)
Two squares of black acetal ("Delrin™" except I think this is some generic brand) laser-cut in the chainring guard pattern. The center area of the pattern is filled with circles of various sizes with a small center hole; these are spacersm used to get the right separation between guard and chain. The square on the right is "empty", meaning the guard and spacers are removed and installed on a bicycle, the other is still in place and taped in place/together on its backside. There's a blue Park Tools ruler across the top of the left square, showing that the square is 235mm (9-1/4 inches) wide. (The ruler is legible because I used white-out to fill all the little recessed measurement lines and lettering, then wiped off the excess.)
Close-up-ish of the chainring-and-pedals area of a bicycle parked on the edge of a damp brick sidewalk.

The pink bicycle has a shiny metal guard, and a mirrored acrylic chainring guard that manages to reflect the bricks in good alignment with the pattern on the sidewalk.

The chainring guard has a slot cut so it fits directly over the crank arm, and 3 holes drilled in it for 5 130bcd chainring bolts.  It is attached with long thin screws that go through the hole in the center of each chainring bolt.
Close-up-ish of the chainring-and-pedals area of a bicycle parked on the edge of a damp brick sidewalk. The pink bicycle has a shiny metal guard, and a mirrored acrylic chainring guard that manages to reflect the bricks in good alignment with the pattern on the sidewalk. The chainring guard has a slot cut so it fits directly over the crank arm, and 3 holes drilled in it for 5 130bcd chainring bolts. It is attached with long thin screws that go through the hole in the center of each chainring bolt.