bbb bbc bbo bbt bbw bcb bcc bco bct bob boc boo bot bow btb btc bto btt btw bwb bwc bwo c-- cbb cbc cbo cbt cbw ccb ccc cco cct ccw co- cob coc coo cot cow ctb ctc cto ctt ctw cw- cwb cwc cwo cwt ob- obb obc obo obt obw oc- ocb occ oco oct ocw oo- oob ooc ooo oot oow ot- otb otc oto ott otw owb owc owo owt oww tbb tbc tbo tbt tcb tcc tco tct tcw to- tob toc too tot tow ttb ttc tto ttt ttw twb twc two twt tww wbb wbc wbo wbt wbw wcb wcc wco wct wcw wob woc woo wot wow wtb wtc wto wtt wtw wwc wwo wwt www