fourier variance (variance with more fours)

layout.sty

@@ -892,6 +892,8 @@ interior code={ \path[tcb fill interior] ([xshift=-2mm]interior.west)
   \setcounter{r3c}{1}
 \newcounter{r4b}
   \setcounter{r4b}{\day}
+  \divide\value{r4b} by 7
+  \stepcounter{r4b}
 
 \newcounter{rn4tn1}
   \setcounter{rn4tn1}{-3}