5 letter words:
frets8,
4 letter words:
efts7,
fest7,
fets7,
fret7,
refs7,
reft7,
serf7,
tref7,
erst4,
rest4,
rets4,
tres4,
3 letter words:
efs6,
eft6,
fer6,
fes6,
fet6,
ref6,
ers3,
res3,
ret3,
ser3,
set3,
2 letter words:
ef5,
fe5,
er2,
es2,
et2,
re2,
