Specify the parameters of a rectangular grid in one or more windows.
If the command is started from the graphical window's menu, the context menu
or by a mouse stroke then the destination window is implicitly assumed.
In all other cases the destination window must be explicitly defined if the
window layout contains more than one window.
The destination window is identified by a digitized point or by typing its
identifier. Since the identifiers are powers of two (e.g. 1, 2, 4, ...) a
set of destination windows can be defined by adding the identifiers of all
windows of the set (e.g. 1 + 2 + 4 for windows 1, 2 and 4). A destination set
containing all windows is indicated by the identifier -1.