These 12 qualities are determined by the letter form, line form, and formatting. The shape of letters, the curvature of letters, the angle or slant of characters, the proportionate size of letters, and the use and appearance of connecting lines between letters are all examples of letter form. The way words are put together to form sentences, the number and length of words in a sentence, and the amount of space between words are all examples of line form. Finally, the arrangement of letters on the page, the typeface used, the color of ink, and any other formatting features such as footnotes or endnotes are all examples of formatting. The three main categories of handwriting quality are regular, irregular, and mixed-handwriting samples. Regular handwriting has letters that are close to the same size, have straight edges, and lack any indentations or strokes that extend beyond the boundaries of the character. Irregular handwriting includes letters that vary in size or that have extensions that touch or overlap other letters. Mixed-handed writing is defined as using both hands for writing; each hand may be used for writing letters of the alphabet separately or together. It is important to understand that although letters may be written by either hand, it does not mean that they were not guided by the mind when being crafted. Handwriting samples can be found in official documents, such as contracts, wills, and diplomas.