Hold the current graph.
HOLD ON holds the current plot and all axis properties so that
subsequent graphing commands add to the existing graph.
HOLD OFF returns to the default mode whereby PLOT commands erase
the previous plots and reset all axis properties before drawing
HOLD, by itself, toggles the hold state.
HOLD does not affect axis autoranging properties.
HOLD ON sets the NextPlot property of the current figure and
axes to "add".
HOLD OFF sets the NextPlot property of the current axes to
See also ISHOLD2AQVQRR, NEWPLOT , FIGURE , AXES .