Data normal; 
  do X = -2.5 to 2.5 by .1; do Y = -2.5 to 2.5 by .1; 
  fxy = exp( -.5*(X*X + Y*Y + .8*X*Y)); 
  if abs(X-round(2*X)/2)<.001  or abs(Y-round(2*Y)/2)<.001 then clr = "green"; 
  else clr="red"; 
  output; end; end;
proc means data=normal nway; var fxy; class X; output out=Xmarg mean=mx; 
proc means data=normal nway; var fxy; class Y; output out=Ymarg mean = my;
data all ; 
set normal Xmarg Ymarg; shapevar = "Prism   "; output; 
hold=Y; Y=2.6; fxy= 2*mx;shapevar = "balloon"; output; 
 X=2.6; Y=hold; fxy = 2*my;shapevar = "balloon"; output;   
  proc g3d data=all; scatter X*Y=fxy/shape=shapevar color=clr; 
  run;