#include <bits/stdc++.h>
using namespace std;
int N, M;
char A[55][55];
int main() {
  scanf("%d%d", &N, &M);
  for (int i = 1; i <= N; i++) scanf("%s", A[i] + 1);
  for (int i = 1; i <= N; i++) {
    for (int j = 1; j <= M; j++) {
      if (A[i][j] == '#' && (A[i - 1][j] == '.' || !(i - 1)) &&
          (A[i][j - 1] == '.' || !(j - 1)) &&
          (A[i + 1][j] == '.' || i + 1 > N) &&
          (A[i][j + 1] == '.' || j + 1 > M))
        return puts("No");
    }
  }
  puts("Yes");
  return 0;
}
