#include<bits/stdc++.h>
using namespace std;
int main() {
	int H, W;
	cin >> H >> W;
	char A[H][W];
	for (int i = 0; i < H; i++) {
		for (int j = 0; j < W; j++) {
			cin >> A[i][j];
		}
	}
	int x[4] = { 1,0,-1,0 };
	int y[4] = { 0,1,0,-1 };
	bool flg = true;
	for (int i = 0; i < H; i++) {
		for (int j = 0; j < W; j++) {
			//A kakutei
			int cnt=0;
			for (int s = 0; s < 4; s++) {
				for (int t = 0; t < 4; t++) {
					if ((j + x[s]) < 0 || (j + x[s]) >= W) {
						continue;
					}
					else if ((i + y[t]) < 0 || (i + y[t]) >= H) {
						continue;
					}
					else {
						if (A[i + x[s][j + y[t] == '.') {
							cnt++;
					 }
					}
				}
			}
			if (cnt == 4) {
				flg = false;
			}
		}
	}
	if (flg) {
		cout << "Yes" << endl;
	}
	else {
		cout << "No" << endl;
	}
	return 0;
}