makewordlevel:=proc(g,n)
    local i,j,k,i2,l,word,wordlist,wordlist2;
    wordlist:=[[g[1]],[g[2]],[g[3]],[g[4]]]; # Start with generator list
    for l from 1 to n-1 do
    wordlist2:=[[],[],[],[]];      # For next level, start with empty list
    for i from 1 to 4 do           # Work on list of words ending with g[i]
       for j from -1 to 1 do       # Add new generator to end of each word
          i2:= (i+ j -1 mod 4) +1; # i2 must be 1, 2, 3, or 4
          for k from 1 to nops(wordlist[i]) do
#             word:=""||(wordlist[i,k])||(g[i2]); # Word concatenation
             word:=wordlist[i,k].g[i2];  # Matrix multiplication
             wordlist2[i2]:=[op(wordlist2[i2]),word];
          end do;
       end do;
    end do;
    wordlist:=wordlist2;
    end do;
    RETURN(wordlist)
end proc:

makeallwords:=proc(g,n)
    local wordlist, i;
    wordlist:=map(op,makewordlevel(g,1));
    for i from 2 to n do
        wordlist:=[op(wordlist),
              op( map(op,makewordlevel(g,i))) ];
    end do:
    RETURN(wordlist);
end proc: