bbbb bobb bobo bobu bobw boob boot boow botb boto bott botw bout bouw bowt btob bttb btwo bubb bubo bubu but- buto butt obbo obot oooo ootb ootw oto- otoo otow otto ottu otwo out- outb outo ouu- owow owt- owtt tobo tobt tobu toot toto tott tout ttbb tttt tubb tubo tubu tuto tutt tutu tuuo twbt two- twob twoo twot ubbo utto uttu utwo uuuu wbbb wbbo wbbt wbbw wbob wbow wbto wbtt wbtu wbtw wbut wbuw wbwb wbwo wbwt wobb wobo wobt woob woot woow wotb wott wotw woub wout wouw wowb wowo wowt woww wtbb wtbo wtbu wtob wtot wtou wtow wttb wtto wttt wttu wttw wtwb wtwo wtwt wtww wubb wubt wubu wuot wutb wutu wuub wuuu wwbb wwbt wwbu wwot wwow wwtw wwww