4 letter words:
birk10,
bork10,
brik10,
grok9,
biog7,
brig7,
brog7,
biro6,
brio6,
giro5,
gori5,
3 letter words:
bok9,
kob9,
irk7,
kir7,
koi7,
kor7,
oik7,
rok7,
big6,
bog6,
gib6,
gob6,
bio5,
boi5,
bor5,
bro5,
obi5,
orb5,
rib5,
rob5,
gio4,
gor4,
rig4,
2 letter words:
ki6,
ko6,
bi4,
bo4,
ob4,
gi3,
go3,
io2,
oi2,
or2,