A cucoloris is essentially a mask placed in front of a light source for the purpose producing a shadow of some shape (which can be abstract or actual). Used extensively in theatre and film, and sometimes in photography and television.
If you want to design your own, I suggest to use a black square with the shape(s) cut out of it. Even if the shape’s width and height are not the same, please use a square as the base because the frames of cucoloris holders tend to be square shaped.
Also, please leave enough black space near the edges to allow for a person to be holding it with his/her hands or for clips to be safely attached to your design, so it does not fall off the light (which can be quite high on stage or in a studio) and does not hurt/kill somebody.
Which brings me to the disclaimer: Use this design at your own risk. It is your own responsibility to to mount the lights and the cucolorises properly and with utmost safety in mind. See the movie Thunderpants (2002) for what can happen if any light equipment is not mounted safely!