TDKKTTTT; KKKK
TDKKTKTK; DKDK
TDKKTTTT; KKKK TTTT KKKK
1-+-2-+-3-+-4-+- DkkDkkBkDkkDkkBk; DkkDkkBk-ttktktk k DtttB-DtttB-Dttt; kkkk kkkk kkkk B-DtttB-DtttB---; kkkk kkkk