import numpy as np
import sys

w, h = map(int, sys.stdin.readline().strip().split(" "))

a = np.zeros((w,h), dtype=int)

for i in range(w):
    l = sys.stdin.readline().strip()
    for j in range(h):
        a[i, j] = (l[j] == "#")

for i in range(w):
    for j in range(h):
        if a[i, j] == 0:
            continue
        check = True
        if i >= 1:
            check &= a[i-1, j] == 0
        if i < h-1:
            check &= a[i+1, j] == 0
        if j >= 1:
            check &= a[i, j-1] == 0
        if j < w-1:
            check &= a[i, j+1] == 0
        if check:
            print("No")
            quit()
print("Yes")