).An em space was the width of a capital letter "M" – as wide as it was high – while an en space referred to a space half the width of its height (usually the dimensions for a capital "N").Individual letters are assembled into words and lines of text with the aid of a composing stick, and the whole assembly is tightly bound together to make up a page image called a "forme", where all letter faces are exactly the same height to form a flat surface of type.