title " "; 
data A; 
do x1 = -10 to 10 ; 
do x2 = -10 to 10 ; 
    Y = 25 + .1*X1 + .3*X2 - .05*X1 *X2 + 2*normal(5431875);
output; end; end;  
proc g3d; 
  scatter x2*x1=y / shape = "balloon" size=0.5 noneedle rotate=15; 
  run; 
proc reg data=a; 
  model Y = x1 x2; 
  output out=out1 residual=r; 
  run; 
proc gplot; plot r*x1 r*x2/vref=0; 
  symbol1 v=dot i=none;
  Title "3-D Residuals"; 
  run; 
data out1; set out1;  
  color="gray "; shape="balloon"; size=0.5;
  if r<0 then do; color="red"; shape="diamond"; size=0.8; end;  output; 
  r=-10; x1=x1+.00001*(ranuni(12345)-.5); output; 
proc g3d; scatter x2*x1=r / 
  shape = shape size=0.5 color=color tilt=85 noneedle rotate=15 size=size; 
run;