bbbb bbbs bffs bfsi bfsr bibb bibi bibo bibs biff bifi biis biko bio- bioi bios birb biri birk biro birr birs bis- bisk biso biss bobb bobi bobo bobs boff bofs boi- boii bois boki boko boks boob boof book boor boos bor- borf bori bork boro borr bors bosi bosk boso boss brik brio bris brkb brob brok broo bror bros brrr brrs brsb brsr bsff bsfs bsos f--k fbis fbrs ffff ffii ffrr ffss fibs fiff fifi fifo fiii fiki fior fios firk firs fisi fisk fiss fobs fofo fois foki foof fook foos for- forb fori fork foro forr fors fosb fosi foso foss frib frik frio fris frob fros frsb frso fsfi fsfo fssf ibfi ibis ibos ibri ibro ibsf ibss ifbb ifis ifor ifrb ifrf ifri ifsb ifso iiii iiio iiis iioi iioo iios iirs iisi iisr ikki ikko ikoo ikri iobi ioii ioio ioko ioof iooi iooo ioos iori iors ioso iri- irio iris irki irks irob irri irrs irsf isis iskf isko iso- isof isok isor isos isri issf issi isso issr isss k-os kbbb kbbf kbbi kbbk kbbo kbbr kbbs kbfb kbff kbfi kbfk kbfo kbfr kbfs kbib kbif kbik kbio kbis kbkb kbkf kbkk kbko kbkr kbob kboi kbok kboo kbos kbrb kbrf kbri kbrk kbro kbsb kbsi kbsk kbso kbsr kbss kfbk kffb kfff kffk kfio kfir kfis kfkb kfok kfoo kfor kfri kfro kfrr kfrs kfsi kfsk kfsr kibb kibi kibo kibr kibs kiff kifr kifs kiii kiik kiis kikf kiki kikk kiko kikr kioi kiok kioo kirb kirf kiri kirk kiro kirr kirs kisf kisi kisk kiso kisr kiss kkbb kkbi kkbo kkbr kkbs kkfi kkfr kkfs kkik kkkk kkob kkoo kkor kkrb kkrf kkrk kkro kkrr kkrs kksf kksi kksr kkss kobb kobi kobk kobo kobr kobs koff kofi kofk kofo koii koir kokb kokf koki kokk koko kokr koks koob kooi kook kooo koor koos korb korf kori kork koro korr kors kos- kosb kosf kosi koso kosr koss krbb krbi krbk krbr krff krfo krfs krib krik krio kris krki krkk krko krkr krks krob krof kroi krok kroo kror kros krrb krrf krri krrk krro krrr krrs krsf krsk krsr krss ksbi ksbr ksbs ksfb ksfi ksfo ksfr ksib ksif ksii ksik ksir ksis kskb kskf kskk ksko kskr ksks ksob ksof ksoi ksok ksoo ksor ksos ksrb ksrf ksro ksrr ksrs kssi ksso kssr ksss obbo obis obkb oboi obok obor obos obri obro obsr obss off- offo offr offs ofik ofor oiii oiko oiks oios okir okko okok okor okro oksi okso oobi ooff oofs oooo ooos oosi orbb orbi orbo orbs orff orfi orfs ori- orif orio oris orko oro- orof orok oror oros orri orro orrs orsi orsk orso osii osik osis oski osoi osoo osor osos osro ossb ossi osso rbbb rbbr rbbs rbis rbss rib- ribo ribs riff rifs riif riis riki rikk rios riri rirs risi risk riso riss rkkf rkos rkss rob- robb robi robo robs roff rofo roif roik roio roir rois roki rokk roko rokr roks roob roof rooi rook roor roos rori rork roro rosi roso ross rrif rrrr rsbi rsis rsos s-ib s-ii s-os sbbs sbor sbrk sbsi sfio sfor sfos sfro sfss sibi sibo sibs siff sifo sifr siik siki siko sikr siks sior sios sirf siri sirk siro sirr sirs sisi sisk siss skif skik skio skir skis skor skss sobo sobr sobs sofi sofo soif soik soir sois soki sokk soko soof sook soor soos sorb sori soro sorr sors sosi soso soss srfi srib sris sros ssbr ssis ssri ssrs sssb sssf sssi ssss