rpyf pryf rypf yrpf pyrf yprf rpfy prfy rfpy frpy pfry fpry ryfp yrfp rfyp fryp yfrp fyrp pyfr ypfr pfyr fpyr yfpr fypr
Note: these 'words' (valid or invalid) are all the permutations of the word rpyf. These words are obtained by scrambling the letters in rpyf.