H,W = map(int,input().split())
lists = [input() for i in range(W)]
x = 1
y = 1
for i in range(H):
    lists[i] = list(lists[i])
lists1 = []
lists2 = []
for i in range(W+1):
    lists1.append(".")
for i in range(W+1):
    lists2.append(".")
for i in range(H):
    lists[i].append(".")
lists2 = lists
check = True
while(x<W-1 and y<H-1):
    if(lists2[x][y] == "#"):
        if(x!=0 or y!=0 or x==W-1or y==H-1):
            if((lists2[x+1][y] == ".") and (lists2[x-1][y] == ".") and (lists2[x][y-1] == ".") and (lists2[x][y+1] == ".")):
                check = False
    x = x+1
    y = y+1
if(check):
    print("Yes")
else :
    print("No")