Used to form complex plots of more than one dataset. It has the following modes:
NEW - create a new multiple dataset
APPend - add further data to an existing multiple dataset
DELete - remove data from a multiple dataset
SPLit - create multiple dataset by splitting 2D dataset
SHOw - list content and status of dataset
COMbine - combine data into single plots (overlays)
LAYout - define layout of plots on display surface
HELp - list above options and reprompt
More detailed information on the different modes is given in the
specific sub-section.