e-one eeeee eepee enone enope enpo epeen epene epone exene exxon n-p-n nenno neope neppe nexen nexoe nexon nnooo no-no no-op nonne nonno nonop noone nopep noppe noxon oeno- oenoe oeppo one-x onene oneno oneon oneop onne- onnen onone onoon onpop onxeo ooooo openx opepe opone oppon p-n-p p-o-x peene pene- penex penne penon peone pepee pepon peppe pneo- po-on po-po ponne poope poopo popex popon popop poppe poppo poxon pppox x-one xeno- xenon xepon xexex xonox xoxox