Semigraphics

The first one is to create a low-resolution all points addressable mode using a set of special characters with all binary combinations of a certain subdivision matrix of the text mode character size; this method is referred to as block graphics,[1] or sometimes mosaic graphics.

[2][3] The second one is to use special shapes instead of glyphs (letters and figures) that appear as if drawn in raster graphics mode, sometimes referred to as semi- or pseudo-graphics; an important example of this is box-drawing characters.

Single and double lines are still often drawn with this method when the system uses text mode; for example when running the BIOS setup program.

[4] For example, an 8×12 pixel character could be divided vertically in two halves and horizontally in three parts, and then assigning "ink" and "background" values to the elements of the matrix in a binary pattern, corresponding to the binary sequence of the position in the font table of a 2×3 block mosaic[5] matrix of so-called squots (square dots)[6] or sextants.

[21] The original PET relied to such a degree on these characters that it printed them on its keyboard, as can be seen here, an example that other systems soon copied.