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import java.io.*;
import java.util.*;

/*
TASK: Main
LANG: JAVA
 */
public class Main {
    static int n , m;
    static boolean good;
    static HashSet<Integer> x , y;
    static String tmp;
    static boolean[][] grid , used;
    static boolean[] seen;
    static ArrayList<coord>[][] graph;

    public static void main(String[] args) throws IOException {
        FastScanner in = new FastScanner(System.in);
        n = in.nextInt();
        m = in.nextInt();
        grid = new boolean[n][m];
        graph = new ArrayList[n][m];
        seen = new boolean[n];
        good = true;
        for(int i = 0;i < n; i++){
            tmp = in.next();
            for(int j = 0;j < m; j++){
                grid[i][j] = tmp.charAt(j) == '#';
                if(grid[i][j])graph[i][j] = new ArrayList<coord>();
            }
        }
        for(int i = 0;i < n; i++){
            for(int j =0;j < m; j++){
                if(grid[i][j]) {
                    for (int k = i + 1; k < n; k++) {
                        if (grid[k][j]) {
                            graph[i][j].add(new coord(k, j));
                            break;
                        }
                    }
                    for (int k = i - 1; k >= 0; k--) {
                        if (grid[k][j]) {
                            graph[i][j].add(new coord(k, j));
                            break;
                        }
                    }
                    for (int k = j + 1; k < m; k++) {
                        if (grid[i][k]) {
                            graph[i][j].add(new coord(i , k));
                            break;
                        }
                    }
                    for (int k = j - 1; k >= 0; k--) {
                        if (grid[i][k]) {
                            graph[i][j].add(new coord(i , k));
                            break;
                        }
                    }
                }
            }
        }
        for(int i = 0;i < n; i++){
            if(!seen[i]){
                for(int j = 0;j < m; j++){
                    if(grid[i][j]){
                        used = new boolean[n][m];
                        x = new HashSet<Integer>();
                        y = new HashSet<Integer>();
                        dfs(i , j);
                        for(Integer a : x){
                            for(Integer b : y){
                                if(!grid[a][b]){
                                    System.out.println("No");
                                    return;
                                }
                            }
                        }
                        break;
                    }
                }
            }
        }
        System.out.println("Yes");
    }
    private static void dfs(int a , int b){
        if(used[a][b])return;
        used[a][b] = true;
        seen[a] = true;
        x.add(a);
        y.add(b);
        for(coord c : graph[a][b]){
            dfs(c.x , c.y);
        }
    }
    private static class coord{
        int x , y;
        public coord(int a , int b){
            x = a;
            y = b;
        }
    }

    private static class FastScanner {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public FastScanner(InputStream stream) {
            this.stream = stream;
        }

        int read() {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) return -1;
            }
            return buf[curChar++];
        }

        boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        boolean isEndline(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String next() {
            int c = read();
            while (isSpaceChar(c)) c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public String nextLine() {
            int c = read();
            while (isEndline(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndline(c));
            return res.toString();
        }
    }
}