data homework; input block entry; 
cards; 
   1        3
   1        6
   1        9
   1       11
   2        3
   2        4
   2        8
   2       12
   3       10
   3       11
   3       12
   3       13
   4        2
   4        5
   4        8
   4       11
   5        7
   5        8
   5        9
   5       10
   6        4
   6        5
   6        6
   6       10
   7        1
   7        5
   7        9
   7       12
   8        3
   8        5
   8        7
   8       13
   9        1
   9        2
   9        3
   9       10
  10        2
  10        4
  10        9
  10       13
  11        1
  11        4
  11        7
  11       11
  12        1
  12        6
  12        8
  12       13
  13        2
  13        6
  13        7
  13       12
; 
** Use IML to set up dummy matrix of 0s then 
insert 1s to get incidence matrix ***;
%let fmt=[colname=name rowname=name format=2.0]; 
 proc iml; 
use homework; 
read all var{entry block} into D; 
print D; 

name = {'1' '2' '3' '4' '5' '6' '7' '8'
'9' '10' '11' '12' '13'};

A = shape(0,13,13); 
print A &fmt;

do row = 1 to 52; 
A[D[row,1] ,D[row,2]]=1; 
end; 
print A &fmt;  
run; 


** Now use this matrix to prove that 
the design is a BIB ***;