yaabc ayabc yaabc ayabc aaybc aaybc yabac aybac ybaac byaac abyac bayac yabac aybac ybaac byaac abyac bayac aabyc aabyc abayc baayc abayc baayc yaacb ayacb yaacb ayacb aaycb aaycb yacab aycab ycaab cyaab acyab cayab yacab aycab ycaab cyaab acyab cayab aacyb aacyb acayb caayb acayb caayb yabca aybca ybaca byaca abyca bayca yacba aycba ycaba cyaba acyba cayba ybcaa bycaa ycbaa cybaa bcyaa cbyaa abcya bacya acbya cabya bcaya cbaya yabca aybca ybaca byaca abyca bayca yacba aycba ycaba cyaba acyba cayba ybcaa bycaa ycbaa cybaa bcyaa cbyaa abcya bacya acbya cabya bcaya cbaya aabcy aabcy abacy baacy abacy baacy aacby aacby acaby caaby acaby caaby abcay bacay acbay cabay bcaay cbaay abcay bacay acbay cabay bcaay cbaay
Note: these 'words' (valid or invalid) are all the permutations of the word yaabc. These words are obtained by scrambling the letters in yaabc.