or download this
n = 24
...
a|||b|||1~~~a|||b|||2~~~a|||b|||3~~~a|||b|||4~~~a|||b|||5~~~a|||b|||6~
+~~a|||b|||7~~~a|||b|||8~~~a|||b|||9~~~a|||b|||10~~~a|||b|||11~~~a|||b
+|||12~~~a|||b|||13~~~a|||b|||14~~~a|||b|||15~~~a|||b|||16~~~a|||b|||1
+7~~~a|||b|||18~~~a|||b|||19~~~a|||b|||20~~~a|||b|||21~~~a|||b|||22~~~
+a|||b|||23~~~a|||b|||24~~~a|||b|||25~~~a|||b|||26
,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1