All glyphs are represented with a square grid divided equally to the same number of rows and columns. Each cell of the grid is filled with either black or white color. The first and the last row/column of each glyph contains only black cells, which creates a black border around each glyph. Every row and column has at least one white cell, so there are no completely black rows and columns (except the borders). All such glyphs are printed on white paper in such a way, that there is white area around black borders of a glyph (the above picture shows how they look like when printed). I added a PDF file in the Zip file with 4 glyphs ready to be used.