Stairstep graph (bar graph without internal lines).
Stairstep plots are useful for drawing time history plots of
digital sampled-data systems.
STAIRS(Y) draws a stairstep graph of the elements of vector Y.
STAIRS(X,Y) draws a stairstep graph of the elements in vector Y at
the locations specified in X. The X-values must be in
ascending order and evenly spaced.
[XX,YY] = STAIRS(X,Y) does not draw a graph, but returns vectors
X and Y such that PLOT (XX,YY) is the stairstep graph.
See also BAR , HIST .