SUBULIFORM

bi bo if is li lo mi mo mu of oi om or os si so um us

bio bis bos bro bum bur bus fib fil fir flu fob for fou fro fub fur ifs ism lib lis lob lum mib mil mir mis mob mol mor mos mus obi oil oms orb ors our rib rif rim rob rom rub rum sib sim sir sob sol som sou sri sub sum ulu urb

bios birl biro blur boil brim brio bris bros bumf bums burl burs fibs film filo fils firm firs flir flub flus fobs foil forb form foul four from fubs furl furs libs limb limo lobs lour lums mibs milo mils mirs miso mobs moil mols mors obis oils orbs ours ribs rifs rims robs roil rolf roms rubs rums silo slim slob slub slum slur soil soli sorb sori soul sour sulu sumo surf ulus umbo urbs urus