ddd ddf ddi ddt ddx ddy dfd dff dfi dft dfx di- did dif dii dit dix diy dtd dtf dti dtt dtx dty dxd dxi dxt dxx dy- dyd dyy fdd fdf fdi fdt fdx ffd fff ffi fft ffx ffy fid fif fii fit fix ftd ftf fti ftt ftx fty fxi fxt fxx fy- fyi i-d i-f idd idf idi idt idx idy ifd iff ifi ift ifx ify iid iif iii iit iix itd itf iti itt itx ity ixi ixy iyt iyy t-x tdd tdf tdi tdt tdx tdy tfd tff tfi tft tfx tid tif tii tit tix tiy ttd ttf tti ttt ttx tty txf txi txt tyd tyf tyt xdf xdi xdt xft xfx xii xit xix xtf xti xtx xty xxi xxx xxy xyy ydt ydy yfd yff yft yid yif yii yit ytd ytf ytt yxy yyf yyt yyy