Title "Example 1"; 
data type1; input Y X1 X2; datalines; 
-2 -2 1
-3 -1 0
 0  2 0
 2  1 2
 ; 
 proc glm; model Y = x1 x2/xpx i ss1 ss2;
 title "Example 2"; 
 data type1; input Y X1 X2; datalines; 
-2 -2 1
-3  1 0
 0  2 0
 2  1 3
 ; 
 proc glm; model Y = x1 x2/xpx i ss1 ss2;
 run;