Fonts determine what characters will look like in a window. A font is a graphics attribute of a drawable. It is a mapping from a character code to a bit pattern to be drawn in a drawable. Fonts may be fixed width (each character is the same width, like a typewriter or conventional computer terminal) or proportionally spaced (each character takes only the space needed for that character, like a normal typeset book). Fonts come in many sizes, shapes, and styles. They can even write from right to left! But X does not provide for rotated fonts, or fonts that write vertically.