c-cor c-p-c c-pop ccccc co-co co-op cocc- cocco cocto coopt coppo copr- copro copto coro- corop corot corto cott- cotto cpctc croco croop croot cropc cropo crott octo- octor ooooo opto- optot optto orcop oroco ortoo ototo otpor pctct po-po pocop poopo poort popco popop poppo porco poro- porro porto potco potoc potoo potop potor potro potto proor proot prop- propp propr propt prot- proto prtor ptprc ptpro ptprr ptprt r-co- ro-ro rocco rocor roto- rotor rotot rotto rprop rptor t-pop t-top tocco toco- topo- topor topot toppo topto torpo torro torto toto- totoo totop tprot troco troop trop- tropo trott ttttt