Karnaugh For Blind people

Having the problem of teaching digital electronics to a blind student, we designed a haptic 4x4 Karnaugh map in a FreeCAD file to be printed in a witbox BQ 3D printer.
It consists of a simple matrix with holes and cylinders. Each cylinder stands for a '1' or 'X' bit as input in the Karnaugh map. Each square in the matrix has got a hole to insert a cylinder, in case of having a '1' or a 'X' in that box. The column and row headings (Gray code) are in Braille. The final result is the base and the