H,W = list(map(int,input().split()))
import sys

block = [
    list(input()) for i in range(H)
]

isok = [[0] * H] * W

#middle
for i in range(1,H-1):
    for j in range(1,W-1):
        if block[i][i] == '.':
            continue
        else:
            if block[i+1][j] == '#' or block[i][j+1] == '#' or block[i-1][j] == '#' or block[i][j-1] == '#':
                continue
            else:
                print('No')
                sys.exit()

#left
for i in [0]:
    for j in range(1,W-1):
        if block[i][i] == '.':
            continue
        else:
            if block[i+1][j] == '#' or block[i][j+1] == '#' or block[i][j-1] == '#':
                continue
            else:
                print('No')
                sys.exit()

#top
for i in range(1,H-1):
    for j in [0]:
        if block[i][i] == '.':
            continue
        else:
            if block[i+1][j] == '#' or block[i][j+1] == '#' or block[i-1][j] == '#':
                continue
            else:
                print('No')
                sys.exit()

#right
for i in [H-1]:
    for j in range(1,W-1):
        if block[i][i] == '.':
            continue
        else:
            if block[i][j+1] == '#' or block[i-1][j] == '#' or block[i][j-1] == '#':
                continue
            else:
                print('No')
                sys.exit()

#bottom
for i in range(1,H-1):
    for j in [W-1]:
        if block[i][i] == '.':
            continue
        else:
            if block[i+1][j] == '#' or block[i-1][j] == '#' or block[i][j-1] == '#':
                continue
            else:
                print('No')
                sys.exit()

#TL
if block[0][0] == '#':
    if not(block[1][0] == '#' or block[0][1] == '#'):
        print('No')
        sys.exit()

#TR
if block[H-1][0] == '#':
    if not(block[H-2][0] == '#' or block[H-1][1] == '#'):
        print('No')
        sys.exit()

#BL
if block[0][W-1] == '#':
    if not(block[1][W-1] == '#' or block[0][W-2] == '#'):
        print('No')
        sys.exit()

#TL
if block[H-1][W-1] == '#':
    if not(block[H-2][W-1] == '#' or block[H-1][W-2] == '#'):
        print('No')
        sys.exit()



print('Yes')
