An optional argument that specifies the order in which the graphics elements are drawn. The value can be the keyword Back or Forward or an integer that specifies the drawing order for a number of graphics elements. 1 means the object is drawn first.
obj = dt << Bivariate( Y( :weight ), X( :height ) );
Report( obj )[FrameBox( 1 )] <<
Description( "Pen Script" ),
biv = Bivariate( y( weight ), x( height ) );
rbiv = biv << Report;
Wait( 1 );