#include <bits/stdc++.h>
using namespace std;
const long long INF = 1LL << 60;
string operator*(const string& s, int k) {
  if (k == 0) return "";
  string p = (s + s) * (k / 2);
  if (k % 2 == 1) p += s;
  return p;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
struct Edge {
  long long to, cap, rev;
  Edge(long long _to, long long _cap, long long _rev) {
    to = _to;
    cap = _cap;
    rev = _rev;
  }
};
void add_edge(vector<vector<Edge>>& G, long long from, long long to,
              long long cap, bool revFlag, long long revCap) {
  G[from].push_back(Edge(to, cap, (long long)G[to].size()));
  if (revFlag)
    G[to].push_back(Edge(from, revCap, (long long)G[from].size() - 1));
}
long long max_flow_dfs(vector<vector<Edge>>& G, long long v, long long t,
                       long long f, vector<bool>& used) {
  if (v == t) return f;
  used[v] = true;
  for (int i = 0; i < G[v].size(); ++i) {
    Edge& e = G[v][i];
    if (!used[e.to] && e.cap > 0) {
      long long d = max_flow_dfs(G, e.to, t, min(f, e.cap), used);
      if (d > 0) {
        e.cap -= d;
        G[e.to][e.rev].cap += d;
        return d;
      }
    }
  }
  return 0;
}
long long max_flow(vector<vector<Edge>>& G, long long s, long long t) {
  long long flow = 0;
  for (;;) {
    vector<bool> used(G.size());
    for (int(i) = (int)(0); i < (int)(used.size()); i++) used[i] = false;
    long long f = max_flow_dfs(G, s, t, INF, used);
    if (f == 0) {
      return flow;
    }
    flow += f;
  }
}
void BellmanFord(vector<vector<Edge>>& G, long long s, vector<long long>& d,
                 vector<long long>& negative) {
  d.resize(G.size());
  negative.resize(G.size());
  for (int(i) = (int)(0); i < (int)(d.size()); i++) d[i] = INF;
  for (int(i) = (int)(0); i < (int)(d.size()); i++) negative[i] = false;
  d[s] = 0;
  for (int(k) = (int)(0); k < (int)(G.size() - 1); k++) {
    for (int(i) = (int)(0); i < (int)(G.size()); i++) {
      for (int(j) = (int)(0); j < (int)(G[i].size()); j++) {
        if (d[i] != INF && d[G[i][j].to] > d[i] + G[i][j].cap) {
          d[G[i][j].to] = d[i] + G[i][j].cap;
        }
      }
    }
  }
  for (int(k) = (int)(0); k < (int)(G.size() - 1); k++) {
    for (int(i) = (int)(0); i < (int)(G.size()); i++) {
      for (int(j) = (int)(0); j < (int)(G[i].size()); j++) {
        if (d[i] != INF && d[G[i][j].to] > d[i] + G[i][j].cap) {
          d[G[i][j].to] = d[i] + G[i][j].cap;
          negative[G[i][j].to] = true;
        }
        if (negative[i] == true) negative[G[i][j].to] = true;
      }
    }
  }
}
void Dijkstra(vector<vector<Edge>>& G, long long s, vector<long long>& d) {
  d.resize(G.size());
  for (int(i) = (int)(0); i < (int)(d.size()); i++) d[i] = INF;
  d[s] = 0;
  priority_queue<pair<long long, long long>, vector<pair<long long, long long>>,
                 greater<pair<long long, long long>>>
      q;
  q.push(make_pair(0, s));
  while (!q.empty()) {
    pair<long long, long long> a = q.top();
    q.pop();
    if (d[a.second] < a.first) continue;
    for (int(i) = (int)(0); i < (int)(G[a.second].size()); i++) {
      Edge e = G[a.second][i];
      if (d[e.to] > d[a.second] + e.cap) {
        d[e.to] = d[a.second] + e.cap;
        q.push(make_pair(d[e.to], e.to));
      }
    }
  }
}
void WarshallFloyd(vector<vector<Edge>>& G, vector<vector<long long>>& d) {
  d.resize(G.size());
  for (int(i) = (int)(0); i < (int)(d.size()); i++) d[i].resize(G.size());
  for (int(i) = (int)(0); i < (int)(d.size()); i++) {
    for (int(j) = (int)(0); j < (int)(d[i].size()); j++) {
      d[i][j] = INF;
    }
  }
  for (int(i) = (int)(0); i < (int)(G.size()); i++) {
    for (int(j) = (int)(0); j < (int)(G[i].size()); j++) {
      d[i][G[i][j].to] = G[i][j].cap;
    }
  }
  for (int(i) = (int)(0); i < (int)(G.size()); i++) {
    for (int(j) = (int)(0); j < (int)(G.size()); j++) {
      for (int(k) = (int)(0); k < (int)(G.size()); k++) {
        chmin(d[j][k], d[j][i] + d[i][k]);
      }
    }
  }
}
bool tsort(vector<vector<Edge>>& graph, vector<int>& order) {
  int n = graph.size(), k = 0;
  vector<long long> in(n);
  for (auto& es : graph)
    for (auto& e : es) in[e.to]++;
  priority_queue<long long, vector<long long>, greater<long long>> que;
  for (int(i) = (int)(0); i < (int)(n); i++)
    if (in[i] == 0) que.push(i);
  while (que.size()) {
    int v = que.top();
    que.pop();
    order.push_back(v);
    for (auto& e : graph[v])
      if (--in[e.to] == 0) que.push(e.to);
  }
  if (order.size() != n)
    return false;
  else
    return true;
}
class lca {
 public:
  const int n = 0;
  const int log2_n = 0;
  std::vector<std::vector<int>> parent;
  std::vector<int> depth;
  lca() {}
  lca(const vector<vector<Edge>>& g, int root)
      : n(g.size()),
        log2_n(log2(n) + 1),
        parent(log2_n, std::vector<int>(n)),
        depth(n) {
    dfs(g, root, -1, 0);
    for (int k = 0; k + 1 < log2_n; k++) {
      for (int v = 0; v < (int)g.size(); v++) {
        if (parent[k][v] < 0)
          parent[k + 1][v] = -1;
        else
          parent[k + 1][v] = parent[k][parent[k][v]];
      }
    }
  }
  void dfs(const vector<vector<Edge>>& g, int v, int p, int d) {
    parent[0][v] = p;
    depth[v] = d;
    for (auto& e : g[v]) {
      if (e.to != p) dfs(g, e.to, v, d + 1);
    }
  }
  int get(int u, int v) {
    if (depth[u] > depth[v]) std::swap(u, v);
    for (int k = 0; k < log2_n; k++) {
      if ((depth[v] - depth[u]) >> k & 1) {
        v = parent[k][v];
      }
    }
    if (u == v) return u;
    for (int k = log2_n - 1; k >= 0; k--) {
      if (parent[k][u] != parent[k][v]) {
        u = parent[k][u];
        v = parent[k][v];
      }
    }
    return parent[0][u];
  }
};
class UnionFind {
  vector<int> data;
  long long num;

 public:
  UnionFind(int size) : data(size, -1), num(size) {}
  bool unite(int x, int y) {
    x = root(x);
    y = root(y);
    if (x != y) {
      if (data[y] < data[x]) swap(x, y);
      data[x] += data[y];
      data[y] = x;
    }
    num -= (x != y);
    return x != y;
  }
  bool findSet(int x, int y) { return root(x) == root(y); }
  int root(int x) { return data[x] < 0 ? x : data[x] = root(data[x]); }
  int size(int x) { return -data[root(x)]; }
  int numSet() { return num; }
};
class SumSegTree {
 private:
  long long _sum(long long a, long long b, long long k, long long l,
                 long long r) {
    if (r <= a || b <= l) return 0;
    if (a <= l && r <= b)
      return dat[k];
    else {
      long long s1 = _sum(a, b, 2 * k + 1, l, (l + r) / 2);
      long long s2 = _sum(a, b, 2 * k + 2, (l + r) / 2, r);
      return s1 + s2;
    }
  }

 public:
  long long n, height;
  vector<long long> dat;
  SumSegTree(long long _n) {
    n = 1;
    height = 1;
    while (n < _n) {
      n *= 2;
      height++;
    }
    dat = vector<long long>(2 * n - 1, 0);
  }
  void add(long long i, long long x) {
    i += n - 1;
    dat[i] += x;
    while (i > 0) {
      i = (i - 1) / 2;
      dat[i] += x;
    }
  }
  long long sum(long long a, long long b) { return _sum(a, b, 0, 0, n); }
};
class RmqTree {
 private:
  long long _find(long long a, long long b, long long k, long long l,
                  long long r) {
    if (r <= a || b <= l) return INF;
    if (a <= l && r <= b)
      return dat[k];
    else {
      long long s1 = _find(a, b, 2 * k + 1, l, (l + r) / 2);
      long long s2 = _find(a, b, 2 * k + 2, (l + r) / 2, r);
      return min(s1, s2);
    }
  }

 public:
  long long n, height;
  vector<long long> dat;
  RmqTree(long long _n) {
    n = 1;
    height = 1;
    while (n < _n) {
      n *= 2;
      height++;
    }
    dat = vector<long long>(2 * n - 1, INF);
  }
  void update(long long i, long long x) {
    i += n - 1;
    dat[i] = x;
    while (i > 0) {
      i = (i - 1) / 2;
      dat[i] = min(dat[i * 2 + 1], dat[i * 2 + 2]);
    }
  }
  long long find(long long a, long long b) { return _find(a, b, 0, 0, n); }
};
void divisor(long long n, vector<long long>& ret) {
  for (long long i = 1; i * i <= n; i++) {
    if (n % i == 0) {
      ret.push_back(i);
      if (i * i != n) ret.push_back(n / i);
    }
  }
  sort(ret.begin(), ret.end());
}
vector<long long> lis_fast(const vector<long long>& a) {
  const long long n = a.size();
  vector<long long> A(n, INT_MAX);
  vector<long long> id(n);
  for (int i = 0; i < n; ++i) {
    id[i] = distance(A.begin(), lower_bound(A.begin(), A.end(), a[i]));
    A[id[i]] = a[i];
  }
  long long m = *max_element(id.begin(), id.end());
  vector<long long> b(m + 1);
  for (int i = n - 1; i >= 0; --i)
    if (id[i] == m) b[m--] = a[i];
  return b;
}
bool z_algorithm(string& str, vector<int>& z, long long s) {
  const int L = str.size();
  z.resize(str.size());
  for (int i = 1, left = 0, right = 0; i < L; i++) {
    if (i > right) {
      left = right = i;
      for (; right < L && str[right - left] == str[right]; right++)
        ;
      z[i] = right - left;
      right--;
    } else {
      int k = i - left;
      if (z[k] < right - i + 1) {
        z[i] = z[k];
      } else {
        left = i;
        for (; right < L && str[right - left] == str[right]; right++)
          ;
        z[i] = right - left;
        right--;
      }
    }
    if (z[i] == s) return true;
  }
  return false;
}
bool z_algorithm(string& str, vector<int>& z) {
  const int L = str.size();
  z.resize(str.size());
  for (int i = 1, left = 0, right = 0; i < L; i++) {
    if (i > right) {
      left = right = i;
      for (; right < L && str[right - left] == str[right]; right++)
        ;
      z[i] = right - left;
      right--;
    } else {
      int k = i - left;
      if (z[k] < right - i + 1) {
        z[i] = z[k];
      } else {
        left = i;
        for (; right < L && str[right - left] == str[right]; right++)
          ;
        z[i] = right - left;
        right--;
      }
    }
  }
  return true;
}
struct RollingHash {
  static const int base1 = 1007, base2 = 2009;
  static const int mod1 = 1000000007, mod2 = 1000000009;
  vector<long long> hash1, hash2, power1, power2;
  RollingHash(const string& S) {
    int n = (int)S.size();
    hash1.assign(n + 1, 0);
    hash2.assign(n + 1, 0);
    power1.assign(n + 1, 1);
    power2.assign(n + 1, 1);
    for (int i = 0; i < n; ++i) {
      hash1[i + 1] = (hash1[i] * base1 + S[i]) % mod1;
      hash2[i + 1] = (hash2[i] * base2 + S[i]) % mod2;
      power1[i + 1] = (power1[i] * base1) % mod1;
      power2[i + 1] = (power2[i] * base2) % mod2;
    }
  }
  inline pair<long long, long long> get(int l, int r) const {
    long long res1 = hash1[r] - hash1[l] * power1[r - l] % mod1;
    if (res1 < 0) res1 += mod1;
    long long res2 = hash2[r] - hash2[l] * power2[r - l] % mod2;
    if (res2 < 0) res2 += mod2;
    return {res1, res2};
  }
  inline int getLCP(int a, int b) const {
    int len = min((int)hash1.size() - a, (int)hash1.size() - b);
    int low = 0, high = len;
    while (high - low > 1) {
      int mid = (low + high) >> 1;
      if (get(a, a + mid) != get(b, b + mid))
        high = mid;
      else
        low = mid;
    }
    return low;
  }
};
long long mod_pow(long long x, long long n, long long mod) {
  long long res = 1LL;
  while (n > 0) {
    if (n & 1) res = res * x % mod;
    x = x * x % mod;
    n >>= 1;
  }
  return res;
}
long long mod_inv(long long x, long long mod) {
  return mod_pow(x, mod - 2, mod);
}
class Combination {
 public:
  vector<long long> fact;
  vector<long long> inv;
  long long mod;
  long long mod_inv(long long x) {
    long long n = mod - 2LL;
    long long res = 1LL;
    while (n > 0) {
      if (n & 1) res = res * x % mod;
      x = x * x % mod;
      n >>= 1;
    }
    return res;
  }
  long long nCr(long long n, long long r) {
    return ((fact[n] * inv[r] % mod) * inv[n - r]) % mod;
  }
  long long nPr(long long n, long long r) {
    return (fact[n] * inv[n - r]) % mod;
  }
  long long nHr(long long n, long long r) { return nCr(r + n - 1, r); }
  Combination(long long n, long long _mod) {
    mod = _mod;
    fact.resize(n + 1);
    fact[0] = 1;
    for (int(i) = (int)(0); i < (int)(n); i++) {
      fact[i + 1] = (fact[i] * (i + 1LL)) % mod;
    }
    inv.resize(n + 1);
    for (int(i) = (int)(0); i < (int)(n + 1); i++) {
      inv[i] = mod_inv(fact[i]);
    }
  }
};
long long gcd(long long m, long long n) {
  if (n == 0) return m;
  return gcd(n, m % n);
}
long long lcm(long long m, long long n) { return m / gcd(m, n) * n; }
vector<vector<long long>> mIdentity(long long n) {
  vector<vector<long long>> A(n, vector<long long>(n));
  for (int i = 0; i < n; ++i) A[i][i] = 1;
  return A;
}
vector<vector<long long>> mMul(const vector<vector<long long>>& A,
                               const vector<vector<long long>>& B) {
  vector<vector<long long>> C(A.size(), vector<long long>(B[0].size()));
  for (int i = 0; i < C.size(); ++i)
    for (int j = 0; j < C[i].size(); ++j)
      for (int k = 0; k < A[i].size(); ++k)
        (C[i][j] += (A[i][k] % 1000000007) * (B[k][j] % 1000000007)) %=
            1000000007;
  return C;
}
vector<vector<long long>> mPow(const vector<vector<long long>>& A,
                               long long e) {
  return e == 0       ? mIdentity(A.size())
         : e % 2 == 0 ? mPow(mMul(A, A), e / 2)
                      : mMul(A, mPow(A, e - 1));
}
template <class T>
class RectangleSum {
 public:
  vector<vector<T>> sum;
  T GetSum(int left, int right, int top, int bottom) {
    T res = sum[bottom][right];
    if (left > 0) res -= sum[bottom][left - 1];
    if (top > 0) res -= sum[top - 1][right];
    if (left > 0 && top > 0) res += sum[top - 1][left - 1];
    return res;
  }
  RectangleSum(const vector<vector<T>>& s, int h, int w) {
    sum.resize(h);
    for (int i = 0; i < h; i++) sum[i].resize(w, 0);
    for (int y = 0; y < h; y++) {
      for (int x = 0; x < w; x++) {
        sum[y][x] = s[y][x];
        if (y > 0) sum[y][x] += sum[y - 1][x];
        if (x > 0) sum[y][x] += sum[y][x - 1];
        if (y > 0 && x > 0) sum[y][x] -= sum[y - 1][x - 1];
      }
    }
  }
};
long long _garner(vector<long long>& xs, vector<long long>& mods) {
  int M = xs.size();
  vector<long long> coeffs(M, 1), constants(M, 0);
  for (int i = 0; i < M - 1; ++i) {
    long long mod_i = mods[i];
    long long v = (xs[i] - constants[i] + mod_i) % mod_i;
    v = (v * mod_pow(coeffs[i], mod_i - 2, mod_i)) % mod_i;
    for (int j = i + 1; j < M; j++) {
      long long mod_j = mods[j];
      constants[j] = (constants[j] + coeffs[j] * v) % mod_j;
      coeffs[j] = (coeffs[j] * mod_i) % mod_j;
    }
  }
  return constants.back();
}
template <typename T>
inline void bit_reverse(vector<T>& a) {
  int n = a.size();
  int i = 0;
  for (int j = 1; j < n - 1; ++j) {
    for (int k = n >> 1; k > (i ^= k); k >>= 1)
      ;
    if (j < i) swap(a[i], a[j]);
  }
}
template <long long mod, long long primitive_root>
class NTT {
 public:
  long long get_mod() { return mod; }
  void _ntt(vector<long long>& a, int sign) {
    const int n = a.size();
    assert((n ^ (n & -n)) == 0);
    const long long g = primitive_root;
    long long tmp = (mod - 1) * mod_pow(n, mod - 2, mod) % mod;
    long long h = mod_pow(g, tmp, mod);
    if (sign == -1) h = mod_pow(h, mod - 2, mod);
    bit_reverse(a);
    for (int m = 1; m < n; m <<= 1) {
      const int m2 = 2 * m;
      long long _base = mod_pow(h, n / m2, mod);
      long long _w = 1;
      for (int x = 0; x < m; ++x) {
        for (int s = x; s < n; s += m2) {
          long long u = a[s];
          long long d = (a[s + m] * _w) % mod;
          a[s] = (u + d) % mod;
          a[s + m] = (u - d + mod) % mod;
        }
        _w = (_w * _base) % mod;
      }
    }
  }
  void ntt(vector<long long>& input) { _ntt(input, 1); }
  void intt(vector<long long>& input) {
    _ntt(input, -1);
    const long long n_inv = mod_pow(input.size(), mod - 2, mod);
    for (auto& x : input) x = (x * n_inv) % mod;
  }
  vector<long long> convolution(const vector<long long>& a,
                                const vector<long long>& b) {
    int result_size = a.size() + b.size() - 1;
    int n = 1;
    while (n < result_size) n <<= 1;
    vector<long long> _a = a, _b = b;
    _a.resize(n, 0);
    _b.resize(n, 0);
    ntt(_a);
    ntt(_b);
    for (int i = 0; i < n; ++i) _a[i] = (_a[i] * _b[i]) % mod;
    intt(_a);
    _a.resize(result_size);
    return _a;
  }
};
vector<long long> convolution_ntt(vector<long long>& a, vector<long long>& b,
                                  long long mod = 1224736769LL) {
  for (auto& x : a) x %= mod;
  for (auto& x : b) x %= mod;
  long long maxval = max(a.size(), b.size()) *
                     *max_element(a.begin(), a.end()) *
                     *max_element(b.begin(), b.end());
  if (maxval < 1224736769) {
    NTT<1224736769, 3> ntt3;
    return ntt3.convolution(a, b);
  }
  NTT<167772161, 3> ntt1;
  NTT<469762049, 3> ntt2;
  NTT<1224736769, 3> ntt3;
  vector<long long> x1 = ntt1.convolution(a, b);
  vector<long long> x2 = ntt2.convolution(a, b);
  vector<long long> x3 = ntt3.convolution(a, b);
  vector<long long> ret(x1.size());
  vector<long long> mods{167772161, 469762049, 1224736769, mod};
  for (int i = 0; i < x1.size(); ++i) {
    vector<long long> xs{x1[i], x2[i], x3[i], 0};
    ret[i] = _garner(xs, mods);
  }
  return ret;
}
int popcount3(int x) {
  x = (x & 0x55555555) + (x >> 1 & 0x55555555);
  x = (x & 0x33333333) + (x >> 2 & 0x33333333);
  x = (x & 0x0F0F0F0F) + (x >> 4 & 0x0F0F0F0F);
  x = (x & 0x00FF00FF) + (x >> 8 & 0x00FF00FF);
  x = (x & 0x0000FFFF) + (x >> 16 & 0x0000FFFF);
  return x;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int X, Y;
  int dx[4] = {0, 0, 1, -1};
  int dy[4] = {1, -1, 0, 0};
  bool can = true;
  cin >> X >> Y;
  string board[60];
  for (int(i) = (int)(0); i < (int)(X); i++) cin >> board[i];
  for (int(i) = (int)(0); i < (int)(X); i++) {
    for (int(j) = (int)(0); j < (int)(Y); j++) {
      if (board[i][j] == '#') {
        int cnt = 0;
        int cnt2 = 0;
        for (int(k) = (int)(0); k < (int)(4); k++) {
          int x = i + dx[k];
          int y = j + dy[k];
          if (x < X && x >= 0 && y < Y && y >= 0 && board[x][y] == '.')
            cnt++;
          else if (!(x > X || x <= 0 || y > Y || y <= 0))
            cnt2++;
          if (k == 3 && cnt + cnt2 == 4) {
            cout << "No" << endl;
            return 0;
          }
        }
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
