a-a a-b a-c aaa aab aac aao aar aaw aax ab- aba abb abc abo abr abw abx ac- aca acb acc aco acr acw acx aoa aob aoc aoo aor aow aox ar- ara arb arc aro arr arw arx aw- awa awb awc awo awr aww ax- axa axo axr axx baa bab bac bao bar baw bax bba bbb bbc bbo bbr bbw bbx bca bcb bcc bco bcr bcx boa bob boc boo bor bow box bra brb bro brr brw brx bwa bwb bwc bwo bwr bxb bxo bxw bxx c-- caa cab cac cao car caw cax cba cbb cbc cbo cbr cbw cbx cca ccb ccc cco ccr ccw ccx co- coa cob coc coo cor cow cox cra crb crc cro crr crw crx cw- cwa cwb cwc cwo cwr cxc cxo cxr cxx oaa oab oac oao oar oaw oax ob- oba obb obc obo obr obw obx oc- oca ocb occ oco ocr ocw ocx oo- ooa oob ooc ooo oor oow oox or- ora orb orc oro orr orx owa owb owc owo oww ox- oxa oxb oxc oxo oxx ra- raa rab rac rao rar raw rax rba rbb rbc rbo rbr rbw rbx rca rcb rcc rco rcr rcw rcx roa rob roc roo ror row rox rra rrb rrc rrr rwa rwb rwc rwr rxr waa wab wac wao war waw wax wba wbb wbc wbo wbr wbw wbx wca wcb wcc wco wcr wcw wcx woa wob woc woo wor wow wox wr- wra wrc wro wrr wrw wrx wwa wwc wwo www wxc wxw xaa xac xar xbc xbr xbx xcb xcr xcx xoa xoc xoo xor xox xrc xrx xwa xxo xxx