bibri biffi bilbi bili- bilif billi billu birur bluff blufi blufr blurb blurr brifu brill brrrr bruff bruiu brull bruri buffi bulb- bulbi buliu bull- bulli bulul burfi burli burri burru fibr- fili- filur flirr fluff flurb flurr fluvi frill fruli fu-fu fullf furil furir ibbur ibill if-- ifill iiiii iliff illui ilulu iluvu irill iuliu li-fi libri libru libuv liivi lilfu liliu lilli liril lirui liuli liviu livvi lubur luiff lulli lulul luuri luvil luvli lviii ri-fi ribbi rubbi rufi- ruili ruiru rulli rvivr ubirr uifli ullur ululu uluru urivi urubu uruli ururi uuuuu v-fib viili viiri villi villu virii viril vivi- vivir vulv-