issei sisei issei sisei ssiei ssiei isesi siesi iessi eissi seisi esisi isesi siesi iessi eissi seisi esisi sseii sseii sesii essii sesii essii issie sisie issie sisie ssiie ssiie isise siise iisse iisse siise isise isise siise iisse iisse siise isise ssiie ssiie sisie issie sisie issie iseis sieis iesis eisis seiis esiis isies siies iises iises siies isies ieiss eiiss iiess iiess eiiss ieiss seiis esiis sieis iseis eisis iesis iseis sieis iesis eisis seiis esiis isies siies iises iises siies isies ieiss eiiss iiess iiess eiiss ieiss seiis esiis sieis iseis eisis iesis sseii sseii sesii essii sesii essii ssiei ssiei sisei issei sisei issei seisi esisi siesi isesi eissi iessi seisi esisi siesi isesi eissi iessi
Note: these 'words' (valid or invalid) are all the permutations of the word issei. These words are obtained by scrambling the letters in issei.