# import
import numpy as np

# input
H, W = map(int, input().split())

Mtmp = []
for _ in range(H):
    tmp = list(input())
    Mtmp.append(tmp)

M = np.array(Mtmp)
S = np.array([[0]*W]*H)

print(M)

digtmp = np.array([[0, 1], [1, 0], [0, -1], [-1, 0]])

def dfs(i, j):
    global ngflag
    global searchflag
    if S[i, j] == 1:
        return
    S[i, j] = 1
    if M[i, j] == '.':
        return
    print("i:{}, j:{}".format(i, j))
    searchflag = 1
    dig = digtmp + np.array([i, j])
    for d in dig:
        if 0 <= d[0] < H and 0 <= d[1] < W:
            if M[d[0], d[1]] == '#':
                ngflag = 0
                dfs(d[0], d[1])

searchflag = 0

while True:
    ngflag = 1
    if 0 not in S:
        if M[target[0], target[1]] == '.':
            ngflag = 0
        break
    target = list(zip(*np.where(S == 0)))[0]
    print("sf:{}, ng:{}".format(searchflag, ngflag))
    dfs(target[0], target[1])
    if M[target[0], target[1]] == '#' and searchflag == 1 and ngflag == 1:
        break
        

print("sf:{}, ng:{}".format(searchflag, ngflag))

if searchflag == 1 and ngflag == 0:
    ans = 'Yes'
elif searchflag == 1 and ngflag == 1:
    ans = 'No'
else:
    ans = 'Yes'

print(ans)
