#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int H,W; cin >> H >> W;
    vector<string> S(H);
    for(auto &s : S) cin >> s;

    vector UL(H,vector<int>(W)),UR = UL,DL = UL,DR = UL;
    for(int i=0; i<H-1; i++) for(int k=0; k<W; k++){
        if(S.at(i).at(k) == '.') continue;
        if(k) DL.at(i+1).at(k-1) = DL.at(i).at(k)+1;
        if(k != W-1) DR.at(i+1).at(k+1) = DR.at(i).at(k)+1;
    }
    for(int i=H-1; i>0; i--) for(int k=0; k<W; k++){
        if(S.at(i).at(k) == '.') continue;
        if(k) UL.at(i-1).at(k-1) = UL.at(i).at(k)+1;
        if(k != W-1) UR.at(i-1).at(k+1) = UR.at(i).at(k)+1;
    }

    vector<vector<int>> R(H,vector<int>(W));
    for(int i=0; i<H; i++) for(int k=0; k<W; k++){
        if(S.at(i).at(k) == '.') continue;
        R.at(i).at(k) = min({UR[i][k],UL[i][k],DR[i][k],DL[i][k]});
    }

    vector<vector<bool>> ok(H,vector<bool>(W));
    for(int i=0; i<H; i++) for(int k=0; k<W; k++){
        if(i-1 >= 0 && k-1 >= 0) continue;
        int x = i,y = k,r = -1;
        stack<pair<int,int>> st;
        while(x < H && y < W){
            if(S.at(x).at(y) == '.'){x++,y++; continue;}
            if(R.at(x).at(y) != 0) r = max(r,R.at(x).at(y));
            if(r == -1) st.push({x,y}); 
            else{
                ok.at(x).at(y) = true;
                while(st.size()){
                    auto [bx,by] = st.top();
                    if(x-bx <= r) ok.at(bx).at(by) = true,st.pop();
                    else break;
                }
                r--;
            }
            x++; y++;
        }
    }
    for(int i=0; i<H; i++) for(int k=0; k<W; k++){
        if(i-1 >= 0 && k+1 < W) continue;
        int x = i,y = k,r = -1;
        stack<pair<int,int>> st;
        while(x < H && y >= 0){
            if(S.at(x).at(y) == '.'){x++,y--; continue;}
            if(R.at(x).at(y) != 0) r = max(r,R.at(x).at(y));
            if(r == -1) st.push({x,y}); 
            else{
                ok.at(x).at(y) = true;
                while(st.size()){
                    auto [bx,by] = st.top();
                    if(x-bx <= r) ok.at(bx).at(by) = true,st.pop();
                    else break;
                }
                r--;
            }
            x++; y--;
        }
    }

    bool yes = true;
    for(int i=0; i<H; i++) for(int k=0; k<W; k++) if(S.at(i).at(k) == '#' && !ok.at(i).at(k)) yes = false;
    if(yes) cout << "Yes" << endl;
    else cout << "No" << endl; 
}