7 letter words:
prepone11,
propene11,
6 letter words:
opener8,
pereon8,
perone8,
reopen8,
repone8,
5 letter words:
opepe9,
preop9,
neper7,
preen7,
prone7,
4 letter words:
peep8,
pepo8,
perp8,
poep8,
pope8,
prep8,
prop8,
repp8,
neep6,
nope6,
open6,
peen6,
peer6,
pene6,
peon6,
pere6,
pern6,
pone6,
pore6,
porn6,
pree6,
repo6,
rope6,
erne4,
oner4,
reen4,
rone4,
3 letter words:
pep7,
pop7,
nep5,
ope5,
pee5,
pen5,
per5,
pre5,
pro5,
rep5,
een3,
ene3,
eon3,
ere3,
ern3,
nee3,
nor3,
one3,
ore3,
ree3,
ren3,
reo3,
roe3,
2 letter words:
op4,
pe4,
po4,
ee2,
en2,
er2,
ne2,
no2,
oe2,
on2,
or2,
re2,
