data test;
   n=_n_;
   input x y z;
   datalines;
1 2 3
1 2 3
2 3 4
3 4 5
3 4 5
4 4 5
;
run;

/* In order to keep the implied ID variable _NAME_ */
/* from causing errors in the second transpose,    */
/* eliminate it using the DROP= data set option    */
proc transpose out=first(drop=_name_);
   by n x;
   var y z;
run;

proc print; run;

proc transpose data=first out=second prefix=a;
   by x;
   var col1;
run;

proc print; 
run;