The macro must modify 0s so that it will output the desired result with its origin at the current point, and increase the current horizontal position by the width of the object. The number registers must also be modified so that they correspond to the result. The appearance of equations is controlled by a large number of parameters. These can be set using the set command. Possible parameters are as follows.
Values are in units of hundredths of an em unless otherwise stated.
These descriptions are intended to be expository rather than definitive. The value is in points. The fat primitive emboldens an equation by overprinting two copies of the equation horizontally offset by this amount. This much horizontal space is inserted on each side of a fraction. The width of subscripts and superscripts is increased by this amount.