opsin posin ospin sopin psoin spoin opisn poisn oipsn iopsn piosn iposn osipn soipn oispn iospn siopn isopn psion spion pison ipson sipon ispon opsni posni ospni sopni psoni sponi opnsi ponsi onpsi nopsi pnosi nposi osnpi sonpi onspi nospi snopi nsopi psnoi spnoi pnsoi npsoi snpoi nspoi opins poins oipns iopns pions ipons opnis ponis onpis nopis pnois npois oinps ionps onips noips inops niops pinos ipnos pnios npios inpos nipos osinp soinp oisnp iosnp sionp isonp osnip sonip onsip nosip snoip nsoip oinsp ionsp onisp noisp inosp niosp sinop isnop sniop nsiop insop nisop psino spino pisno ipsno sipno ispno psnio spnio pnsio npsio snpio nspio pinso ipnso pniso npiso inpso nipso sinpo isnpo snipo nsipo inspo nispo
Note: these 'words' (valid or invalid) are all the permutations of the word opsin. These words are obtained by scrambling the letters in opsin.