=REDUCE(REPT(,SEQUENCE(20,20)),SEQUENCE(20),LAMBDA(s,d,LET(b,SEQUENCE(,20),j,SEQUENCE(20),p,IF(s="",SEQUENCE(20,20)-1,""),m,RANDBETWEEN(3,10),n,RANDBETWEEN(3,10),a,MIN(p),x,MOD(a,20)+1,y,INT(a/20)+1,r,INDEX(p,y,),c,INDEX(p,,x),f,(MAX(c)-a)/20+1,g,REGEXEXTRACT(TEXTJOIN(" ",0,r)&" ","\d+ ")-a+1,h,IF(m>=f,f,m+IF(f-m<3,f-m,)),w,IF(n>=g,g,n+IF(g-n<3,g-n,)),IF(SUM(N(s=""))=0,s,IF((b>=x)*(b<x+w)*(j>=y)*(j<y+h),d,s)))))