aVb aWb aXXb aYb aZb  =>
(      fast)  a{V,W,XX,Y,Z}b
(exhaustive)  a{V,W,XX,Y,Z}b

abcdXegh abcdYfgh  =>
(      fast)  abcd{Xe,Yf}gh
(exhaustive)  abcd{Xe,Yf}gh

ac ad bc bd  =>
(      fast)  {a,b}{c,d}
(exhaustive)  {a,b}{c,d}

ad ae af bd be bf cd ce cf  =>
(      fast)  {a,b,c}{d,e,f}
(exhaustive)  {a,b,c}{d,e,f}

a1b3c a1b4c a2b3c a2b4c a1b5c a2b5c  =>
(      fast)  a{1,2}b{3,4,5}c
(exhaustive)  a{1,2}b{3,4,5}c

fee fie foe fum  =>
(      fast)  f{um,{e,i,o}e}
(exhaustive)  f{um,{e,i,o}e}

one two three four five six seven eight nine ten  =>
(      fast)  {eight,four,six,two,{fiv,thre,{ni,o}n}e,{sev,t}en}
(exhaustive)  {eight,four,six,two,{fiv,thre,{ni,o}n}e,{sev,t}en}

a bx cy dx ey fx g hx i jy aa  =>
(      fast)  {g,i,{,a}a,{b,d,f,h}x,{c,e,j}y}
(exhaustive)  {g,i,{,a}a,{b,d,f,h}x,{c,e,j}y}

a aa aaa aaaa aaaaa anestingtest  =>
(      fast)  a{,a{,a{,{,a}a}},nestingtest}
(exhaustive)  a{,nestingtest,{,{,{,a}a}a}a}

a b  =>
(      fast)  {a,b}
(exhaustive)  {a,b}

ab ac  =>
(      fast)  a{b,c}
(exhaustive)  a{b,c}

aXb aYb  =>
(      fast)  a{X,Y}b
(exhaustive)  a{X,Y}b

a1b3c a1b4c a2b3c a2b4c  =>
(      fast)  a{1,2}b{3,4}c
(exhaustive)  a{1,2}b{3,4}c

/ab/ef/ij/kl /ab/ef/ij/mn /ab/ef/ij /ab/gh/ij/kl /ab/gh/ij/mn /ab/gh/ij /cd/ef/ij/kl /cd/ef/ij/mn /cd/ef/ij /cd/gh/ij/kl /cd/gh/ij/mn /cd/gh/ij  =>
(      fast)  /{ab,cd}/{ef,gh}/ij{,/{kl,mn}}
(exhaustive)  /{ab,cd}/{ef,gh}/ij{,/{kl,mn}}

abdel abdelmn abdelmo abdfgkl abdfgklmn abdfgklmo abdfghkl abdfghklmn abdfghklmo abdfgijkl abdfgijklmn abdfgijklmo acdel acdelmn acdelmo acdfgkl acdfgklmn acdfgklmo acdfghkl acdfghklmn acdfghklmo acdfgijkl acdfgijklmn acdfgijklmo  =>
(      fast)  a{b,c}d{e,fg{,h,ij}k}l{,m{n,o}}

SUCCESS !!