-tree c-cor c-tec ccccc ccett ceco- ceere cefor ceoce ceoor cerc- cerce cerco cerec cerer ceret cero- ceroc cerre cerro certe ceto- cette co-co cocc- cocce cocco coceo cocto coete cofer coffe cofre cooee cooer coore coote corce core- coree corer corfe corfo coro- corot corre corte corto coter cott- cotte cotto crece creer creft creo- creot crete croce croco croft crooe croot crore crote crott ctree cttee ecoff ectfe ecto- ector ectot eeeee efere efetf effer effet efore efter eofor eorre erect erere eroor erore eroto error erte erter etete etoro etree etter feeor feere fefor feoff ferce feret ferr- ferre ferro ferte feter feto- fetor fette focer foore foote force fore- foreo foret forro forte forto fotte freer freet frere frett froot frore frote ftrtt o-fer ocftc ocoee ocote ocree octet octo- octor oeco- offer offof offre offto ofoto ofter oo-er oocre ooooo orcet oreco oreo- orere orero orfeo orfoe orfor oroco oroer orret orter ortet ortoo otere otero otoce ototo otter r-co- recce recco recet rect- recte recto reece reefe reeft reere refco refer refet reffe reffo rere- reree reret retee reter retro rette retto ro-ro rocco rocor roero roffe rofor rooer roofe rooft roore roote rorer roter roto- rotor rotot rotte rotto tefe teoco terce terco teret teror terre terro tert- teter tetr- tetro tette tocco toco- toece toeof toerr toeto tofet toffo tofor tofte toore torce toreo toret torre torro torte torto toter toto- totoe totoo totte treco treer treet trefe treff trere trete trett troco troee trofe troff troft trott ttttt