null[6], lund[5], rund[4], sund[4], runs[4],
lud[4], lus[4], dun[3], und[3], dur[3], nur[3], run[3], sud[3], uds[3], uns[3], rus[3], sur[3], urs[3],
ul[3], du[2], ud[2], nu[2], ur[2],
