An encoder encodes the first 16$16$ lowercase English letters using 4$4$ bits each. The first bit (from the left) of the code is 0$0$ if the letter lies among the first 8$8$ letters, else it is 1$1$, signifying that it lies among the last 8$8$ letters. The second bit of the code is 0$0$ if the letter lies among the first 4$4$ letters of those 8$8$ letters found in the previous step, else it's 1$1$, signifying that it lies among the last 4$4$ letters of those 8$8$ letters. Similarly, the third and the fourth bit each signify the half in which the letter lies.

For example, the letter j$j$ would be encoded as :

• Among (a,b,c,d,e,f,g,h$(a,b,c,d,e,f,g,h$ |$|$ i,j,k,l,m,n,o,p)