yills iylls ylils lyils ilyls liyls yills iylls ylils lyils ilyls liyls yllis lylis yllis lylis llyis llyis illys lilys illys lilys lliys lliys yilsl iylsl ylisl lyisl ilysl liysl yisll iysll ysill syill isyll siyll ylsil lysil yslil sylil lsyil slyil ilsyl lisyl islyl silyl lsiyl sliyl yilsl iylsl ylisl lyisl ilysl liysl yisll iysll ysill syill isyll siyll ylsil lysil yslil sylil lsyil slyil ilsyl lisyl islyl silyl lsiyl sliyl yllsi lylsi yllsi lylsi llysi llysi ylsli lysli yslli sylli lsyli slyli ylsli lysli yslli sylli lsyli slyli llsyi llsyi lslyi sllyi lslyi sllyi illsy lilsy illsy lilsy llisy llisy ilsly lisly islly silly lsily slily ilsly lisly islly silly lsily slily llsiy llsiy lsliy slliy lsliy slliy
Note: these 'words' (valid or invalid) are all the permutations of the word yills. These words are obtained by scrambling the letters in yills.