H, W = map(int, input().split())
S = [[] for _ in range(H)]
for i in range(H):
    S[i] = list(input())

count = [[0] * W for _ in range(H)]
for i in range(H):
    for j in range(W):
        if S[i][j] == '.':
            count[i][j] = 10**7
        else:
            count[i][j] = 0

for i in range(H):
    for j in range(W):
        if S[i][j] == '#':
            if j != W-1 and S[i][j+1] == '#':
                count[i][j] += 1
            if j != 0 and S[i][j-1] == '#':
                count[i][j] += 1
            if i != W-1 and S[i+1][j] == '#':
                count[i][j] += 1
            if i != 0 and S[i-1][j] == '#':
                count[i][j] += 1

check = 0
for i in range(H):
    for j in range(W):
        if count[i][j] < 1:
            check = 1

if check == 0:
    print('Yes')
else:
    print('No')