This braille writing slate was designed to allow anyone who is blind or vision impaired to take braille notes.  The slate opens up to accept any piece of paper, and 4 small rounded nubs in the corners lock the paper in place when the top panel is squeezed down over the paper.  The dots on the bottom panel have been spaced out according to the Braille Authority of North America's guidelines, which you can view here:  https://brailleauthority.org/size-and-spacing-braille-characters

Both panels can be printed without supports and is designed to be held together with the wire from a paper clip.  If you print this on a textured sheet, you may need to add a brim to keep the corners from warping.