C表B2
=IF(B$1="","",IF(SUMPRODUCT((A表!$B$1:$AY$1="開始")*(A表!$B2:$AY2<=B$1)*(B$1<=A表!$C2:$AZ2)),"○","")&IF(SUMPRODUCT((B表!$B$1:$AY$1="開始")*(B表!$B2:$AY2<=B$1)*(B$1<=B表!$C2:$AZ2)),"△",""))
右方向・→下方向・↓
最新のExcelなら
=IF(B$1="","",LET(F,LAMBDA(r,s,IF(SUM(ISEVEN(COLUMN(r))*(r<=B$1)*(B$1<=OFFSET(r,,1))),s,"")),F(A表!$B2:$AY2,"○")&F(B表!$B2:$AY2,"△")))