#include <iostream>
#include <vector>
#include <algorithm>

int main() {
    int H, W;
    std::cin >> H >> W;

    std::vector<std::string> S(H);
    for (int i = 0; i < H; ++i) {
        std::cin >> S[i];
    }

    std::vector<std::vector<int>> maximum_r(H, std::vector<int>(W, H + W));
    

    for (int s = -(W - 1); s < H; ++s) {
        int tmp = 0;
        for (int j = 0; j < W; ++j) {
            int i = s + j;
            if (!(0 <= i && i < H)) {
                continue;
            }

            if (S[i][j] == '#') {
                maximum_r[i][j] = std::min(maximum_r[i][j], tmp);
                ++tmp;
            } else {
                maximum_r[i][j] = -1;
                tmp = 0;
            }
        }

        tmp = 0;
        for (int j = W - 1; j >= 0; --j) {
            int i = s + j;
            if (!(0 <= i && i < H)) {
                continue;
            }

            if (S[i][j] == '#') {
                maximum_r[i][j] = std::min(maximum_r[i][j], tmp);
                ++tmp;
            } else {
                maximum_r[i][j] = -1;
                tmp = 0;
            }
        }
    }
    

    for (int t = 0; t < H + W - 1; ++t) {
        int tmp = 0;
        for (int j = W - 1; j >= 0; --j) {
            int i = t - j;
            if (!(0 <= i && i < H)) {
                continue;
            }

            if (S[i][j] == '#') {
                maximum_r[i][j] = std::min(maximum_r[i][j], tmp);
                ++tmp;
            } else {
                maximum_r[i][j] = 0;
                tmp = 0;
            }
        }

        tmp = 0;
        for (int j = 0; j < W; ++j) {
            int i = t - j;
            if (!(0 <= i && i < H)) {
                continue;
            }

            if (S[i][j] == '#') {
                maximum_r[i][j] = std::min(maximum_r[i][j], tmp);
                ++tmp;
            } else {
                maximum_r[i][j] = -1;
                tmp = 0;
            }
        }
    }

    std::vector<std::vector<int>> final(H, std::vector<int>(W, 0));

    for (int s = -(W - 1); s < H; ++s) {
        int tmp = -1;
        for (int j = 0; j < W; ++j) {
            int i = s + j;
            if (!(0 <= i && i < H)) {
                continue;
            }

            if (maximum_r[i][j] > 0) {
                tmp = std::max(tmp - 1, maximum_r[i][j]);
            } else {
                tmp = tmp - 1;
            }

            if (tmp >= 0) {
                final[i][j] = 1;
            }
        }

        tmp = 0;
        for (int j = W - 1; j >= 0; --j) {
            int i = s + j;
            if (!(0 <= i && i < H)) {
                continue;
            }

            if (maximum_r[i][j] > 0) {
                tmp = std::max(tmp - 1, maximum_r[i][j]);
            } else {
                tmp = tmp - 1;
            }

            if (tmp >= 0) {
                final[i][j] = 1;
            }
        }
    }

    for (int t = 0; t < H + W - 1; ++t) {
        int tmp = 0;
        for (int j = W - 1; j >= 0; --j) {
            int i = t - j;
            if (!(0 <= i && i < H)) {
                continue;
            }

            if (maximum_r[i][j] > 0) {
                tmp = std::max(tmp - 1, maximum_r[i][j]);
            } else {
                tmp = tmp - 1;
            }

            if (tmp >= 0) {
                final[i][j] = 1;
            }
        }

        tmp = 0;
        for (int j = 0; j < W; ++j) {
            int i = t - j;
            if (!(0 <= i && i < H)) {
                continue;
            }

            if (maximum_r[i][j] > 0) {
                tmp = std::max(tmp - 1, maximum_r[i][j]);
            } else {
                tmp = tmp - 1;
            }

            if (tmp >= 0) {
                final[i][j] = 1;
            }
        }
    }

    std::string ans = "Yes";
    for (int i = 0; i < H; ++i) {
        for (int j = 0; j < W; ++j) {
            if (S[i][j] == '#' && !final[i][j]) {
                ans = "No";
            }
        }
    }

    std::cout << ans << std::endl;

    return 0;
}