<\body> provides a few other kinds of additional interfaces to external systems in addition to shell-like interfaces. First of all, it is possible to insert a so called ``executable switch'' anywhere in the document using . For instance, if is installed on your system, then should yield something like . You may enter a expression in the yellow part of this markup, say . Using , you may now switch back and forth between the unevaluated input and the evaluated output *+1|)>>>. This kind of executable switches are very useful for plugins such as >, , , , which are mainly used for the efficient computation and insertion of special graphics inside documents. Some plugins such as can even be selected as a using . When doing so, a special menu will appear, which allows for many useful operations directly on formulas. For instance, when putting the cursor inside the formula and pressing or , the formula gets evaluated automatically to yield . <\initial> <\collection>