#include <iostream>
#include <string>
#include <vector>
#define rep(i,s,N) for(int i=s;i<N;i++)
using namespace std;
int main(void)
{
	int H, W; cin >> H >> W;
	string ini(W+2,'.');
	vector<string> s(H+2,ini);
	rep(i, 1, W+1)cin >> s[i];
	bool flag = true;

	rep(i, 1, H+1) {
		rep(j, 1, W+1) {
			if (s[i][j] == '#'&&s[i - 1][j] == '.'&&s[i + 1][j] == '.'&&
				s[i][j - 1] == '.'&&s[i][j + 1] == '.') {
				flag = false;
				break;
			}
		}
	}
	cout << (flag ? "Yes" : "No") << endl;

	return 0;
}