The de Bruijn menus share one characteristic with the probability menus, in that their layout varies somewhat according to the number of states. Although the number of vertices in the de Bruijn diagram is affected by the number of states as well as the size of the neighborhoods, limits on the range of parameters caused by constraints on the amount of storage space and length of running time are the main reasons for this variability.
There are two kinds of de Bruijn diagrams that can be computed - those showing the counterimages of a uniform string,and those which isolate strings satisfying a certain combination of shifting and periodicity. Letters are assigned to them consecutively, but the combination of period and displacement varies widely because of the differing number of combinations that are possible.
Figure 9 shows the general format of the screen according to the
de Bruijn submenu; the arrangement is slightly different for 
automata because of the large number of combinations which can still be
calculated within modest limitations of space and time. But in all cases,
typing ? will cause the option menu to appear, even after it has been
overwritten during the execution of one of the options.
