import sys
input = sys.stdin.readline
H, W = [int(x) for x in input().split()]
s = []
if H == 1 and W == 1:
    print("Yes")
    sys.exit()
for _ in range(H):
    temp = list(input().rstrip())
    s.append(temp)
def A(i,j,s):
    next_point = [[i+1,j],[i-1,j],[i,j-1],[i,j+1]]
    for n in next_point:
        x, y = n[0], n[1]
        if 0 <= x <= W-1 and 0 <= y <= H-1:
            if s[x][y] == "#":
                return 0
    return 1
for k in range(H):
    for l in range(W):
        flag = 0
        if s[k][l] == "#":
            flag = A(k,l,s)
        if flag:
            print("No")
            sys.exit()
print("Yes")