15.71  SYMBOL 

SYMBOL=symbol
     [LIMITED [VLOG[=ON|OFF]] [[FROM]|TO [[X=]nx,[[Y=]ny[,[Z=]nz]]]
          [RECURSOR] [CURSOR] ]
     [SETS=[FROM] n1 [TO] [n2]]
     [SELECT="name"]
     [POINTS=[FROM] n1 [TO] [n2]]
This  resets  the  symbol  for  the selected data points or sets.  Symbols
should be 0O,1O,...9O, DOT or NONE.  Any other symbol may not be  properly
centered.