Box-drawing characters, also known as line-drawing characters, are a form of semigraphics widely used in text user interfaces to draw various geometric frames and boxes. These characters are characterised by being designed to be connected horizontally and/or vertically with adjacent characters, which requires proper alignment. Box-drawing characters therefore typically only work well with monospaced fonts. In graphical user interfaces, these characters are much less useful as it is more simple and appropriate to draw lines and rectangles directly with graphical APIs. However, they are still useful for command-line interfaces and plaintext comments within source code. Other types of box-drawing characters are block elements, shade characters, and terminal graphic characters, these can be used for filling regions of the screen and portraying drop shadows. Encodings Unicode Box Drawing Unicode includes 128 such characters in the Box Drawing block. In many Unicode fonts only the subset that is also available in the IBM PC character set (see below) will exist, due to it being defined as part of the WGL4 character set. The image below is provided as a quick reference for these symbols on systems that are unable to display them directly: Block Elements The Block Elements Unicode block includes shading characters. 32 characters are included in the block. Symbols for Legacy Computing In version 13.0, Unicode was extended with another block containing many graphics characters, Symbols for Legacy Computing, which includes a few box-drawing characters and other symbols used by obsolete operating systems (mostly from the 1980s): The image below is provided as a quick reference for these symbols on systems that are unable to display them directly: DOS The hardware code page of the original IBM PC supplied the following box-drawing characters, in what DOS now calls code page 437. This subset of the Unicode box-drawing characters is thus included in WGL4 and is far more popular and likely to be rendered correctly: The integral halves are also box drawing as they are used alongside 0xB3: Their number is further limited to 28 on those code pages that replace the 18 characters that combine single and double lines, the left and right half blocks, as well as integral halves with other, usually alphabetic, characters (such as code page 850): Note: The non-double characters are the thin (light) characters (U+2500, U+2502), not the bold (heavy) characters (U+2501, U+2503). Some OEM DOS computers supported other character sets, for example the Hewlett-Packard