h,w = map(int, input().split())
s = [list(input()) for i in range(h)]
s2 = [[0]*(w+2) for i in range(h+2)]
for i in range(h):
    for j in range(w):
        if s[i][j] == '#':
            s2[i+1][j+1] = 1
for i in range(h):
    for j in range(w):
        if s[i][j] == '#':
            if s2[i+1][j] + s2[i+1][j+2] + s2[i][j+1] + s2[i+2][j] == 0:
                print('No')
                exit()
print('Yes')