GraSetAttrMarker | 
ยท GraSetAttrMarker( aAttributes ) => Sets attributes for drawing markers. The array is the same as in Xbase++, and the elements considered are :
Array element               Description                           
GRA_AM_COLOR         Foreground color                              
GRA_AM_SYMBOL      Symbol for marker                             
GRA_AM_BOX             Dimension of a marker in x and y direction