# -*- coding: utf-8 -*-

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

ans = "Yes"
for i in range(0, H):
    for j in range(0, W):
        if i == 0 and j == 0 or i == 0 and j == W-1 or \
            i == H-1 and j == 0 or i == H-1 and j == W-1:
            continue
        if S[i][j] == "#":
            if i == 0:
                if S[i][j+1] != "#" and S[i][j-1] != "#" and S[i+1][j] != "#":
                    ans = "No"
            elif i == H-1:
                if S[i][j+1] != "#" and S[i][j-1] != "#" and S[i-1][j] != "#":
                    ans = "No"
            elif j == 0:
                if S[i][j+1] != "#" and S[i+1][j] != "#" and S[i-1][j] != "#":
                    ans = "No"
            elif j == W-1:
                if S[i][j-1] != "#" and S[i+1][j] != "#" and S[i-1][j] != "#":
                    ans = "No"
        else:
            if S[i][j] == "#" and S[i][j+1] != "#" and S[i][j-1] != "#" \
                and S[i+1][j] != "#" and S[i-1][j] != "#":
                ans = "No"
print(ans)