import java.io.IOException;
import java.util.NoSuchElementException;

import java.io.InputStream;

@SuppressWarnings("unchecked")
public class Main {
    public static void main(String[] args) throws IOException {
        FastScanner fs = new FastScanner();

        final int H = fs.nextInt();
        final int W = fs.nextInt();

        Character[][] s = new Character[H][W];

        for (int i = 0; i < H; i++) {
            String tmp = fs.next();
            s[i] = toCharacterArray(tmp);
        }

        // 下、右、上、左
        int[] dy = { 1, 0, -1, 0 };
        int[] dx = { 0, 1, 0, -1 };

        boolean flg = true;

        for (int y = 0; y < H; y++) {
            for (int x = 0; x < W; x++) {
                if (s[y][x] == '.') continue;

                int cnt = 0;

                for (int k = 0; k < 4; k++)
                {
                    int ny = y + dy[k];
                    int nx = x + dx[k];

                    if (ny < 0 || H <= ny
                        || nx < 0 || W <= nx
                        || s[ny][nx] == '.') continue;

                    cnt++;
                }

                if (0 == cnt) {
                    flg = false;
                    break;
                }
            }

            if (!flg) break;
        }

        System.out.println(flg ? "Yes" : "No");
    }

    static Character[] toCharacterArray(String s) {
        if ( s == null ) {
            return null;
        }

        int len = s.length();
        Character[] array = new Character[len];
        for (int i = 0; i < len ; i++) {
            array[i] = new Character(s.charAt(i));
        }

        return array;
    }
}

class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        } else {
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() {
        if (hasNextByte()) return buffer[ptr++];
        else return -1;
    }
    private static boolean isPrintableChar(int c) {
        return 33 <= c && c <= 126;
    }
    public boolean hasNext() {
        while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
        return hasNextByte();
    }
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true) {
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            } else if(b == -1 || !isPrintableChar(b)) {
                return minus ? -n : n;
            } else {
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE)
            throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() {
        return Double.parseDouble(next());
    }
}


Measured memory_bytes: 23124