9 5
.....
#....
..#..
.....
.#..#
...#.
.#...
....#
.....
 4 10
..#......#
.....##...
#.........
.#.......#
 50 2
..
..
#.
..
.#
..
..
..
.#
..
..
.#
##
..
..
..
.#
..
..
.#
..
..
.#
..
..
.#
..
.#
..
.#
..
.#
.#
.#
..
..
..
.#
.#
.#
..
..
.#
.#
..
..
..
..
..
..
 2 50
...#.##.###...#.#..##....##..........#.#..#.#####.
...#.##.###...#.#..##....##..........#.#..#.#####.
 1 1
#
 3 3
.##
#.#
##.
 50 8
.....#..
........
........
.....#..
.....#..
........
........
........
........
...#....
...#....
........
...#....
#.#.#...
...#....
...#....
........
...#....
...#....
...#....
........
#.#.#...
.....#..
........
#.#.#...
#.#.#...
#.#.#...
...#....
........
........
........
#.#.#...
........
.....#..
........
........
........
........
........
........
.....#..
........
........
........
.....#..
#.#.#...
...#....
........
........
........
 1 1
.
 25 16
.............#..
.............#..
.......#...#....
............#...
.....#..........
.....#..........
#...............
................
........#.......
................
................
.#..............
#...............
.....#..........
.#..............
............#...
................
................
................
........#.......
..#.............
..........#.....
.......#...#....
.............#..
..........#.....
 25 16
..............#.
................
...#...#........
........#.#.....
..............##
..............#.
.......#........
......#.........
............#...
.........#.....#
..............#.
.......#........
#...........#...
...#.#..........
.#..............
................
......#.....#...
.......#........
........#.....#.
................
......#.........
..#.............
................
...#.#..........
.#..............
 10 15
.......#.......
.....#.........
....#..........
....#..........
.....#.........
.....#.........
#.............#
...#..#........
...............
.............#.
 4 10
###..#..##
...##..#..
.##..#..#.
.........#
 2 5
.####
#..##
 5 2
##
##
..
##
..
 2 2
##
#.
 50 1
.
.
#
.
#
.
#
.
.
#
#
#
.
#
#
#
#
.
.
.
.
.
.
.
.
.
#
#
#
#
.
.
.
.
.
#
.
.
.
#
#
.
.
#
#
.
.
#
#
.
 5 2
#.
##
##
#.
..
 2 3
#.#
###
 2 1
.
#
 2 3
#.#
##.
 10 10
..........
..........
..........
..........
.#.......#
#.........
......#...
..........
..........
#.....#...
 4 4
###.
##.#
#.##
.###

No
 No
 No
 Yes
 Yes
 No
 Yes
 Yes
 Yes
 No
 Yes
 No
 No
 Yes
 No
 Yes
 No
 No
 Yes
 No
 No
 No

import java.io.*;
import java.util.*;
import java.io.IOException;
import java.io.InputStream;

import static java.lang.Math.ceil;
import static java.lang.Math.toDegrees;

public class Main {
    public static void main(String[] args) {

        File file = new File("in.txt");
        File fileOut = new File("out.txt");
        InputStream inputStream = null;
        OutputStream outputStream = null;
        // try {inputStream= new FileInputStream(file);} catch (FileNotFoundException ex){return;};
//        try {outputStream= new FileOutputStream(fileOut);} catch (FileNotFoundException ex){return;};
        inputStream = System.in;
        outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }


}

class Task {
    public void solve(int testNumber, InputReader in, PrintWriter out) {
        int n = in.nextInt();
        int m = in.nextInt();
        String[] map = new String[n];
        for(int i=0; i<n; i++){
            map[i] = in.next();
        }

        for(int i=0; i<n; i++){
            Set<Integer> cond = setPos(map[i]);
            if(!check(map,cond)){
                out.println("No");
                return;
            }
        }

        out.println("Yes");





    }


    public Boolean check(String[] map, Set<Integer> cond){
        for(int i=0; i<map.length; i++){
            String row = map[i];
            Set<Integer> sec = setPos(row);
            Set<Integer> inter = new HashSet<>(sec);
            inter.retainAll(cond);
            if(inter.size() == 0){
                return Boolean.TRUE;
            }
            if(sec.size() != cond.size()){
                return Boolean.FALSE;
            }

            for(Integer pos : cond){
                if(!sec.contains(pos)){
                    return Boolean.FALSE;
                }
            }
        }
        return Boolean.TRUE;
    }


    public Set<Integer> setPos(String row){
        Set<Integer> l = new HashSet<>();
        for(int i=0; i<row.length(); i++){
            if(row.charAt(i) == '#'){
                l.add(i);
            }
        }
        return l;
    }



}


class InputReader {
    public BufferedReader reader;
    public StringTokenizer tokenizer;

    public InputReader(InputStream stream) {
        reader = new BufferedReader(new InputStreamReader(stream), 32768);
        tokenizer = null;
    }

    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    }

    public String nextLine(){
        try {
            return reader.readLine();
        } catch (IOException e){
            throw new RuntimeException(e);
        }
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }
    public long nextLong() { return Long.parseLong(next()); }

}



class Pair<F, S> {
    public final F first;
    public final S second;




    public Pair(F first, S second) {
        this.first = first;
        this.second = second;
    }

    @Override
    public boolean equals(Object o) {
        if (!(o instanceof Pair)) {
            return false;
        }
        Pair<?, ?> p = (Pair<?, ?>) o;
        return Objects.equals(p.first, first) && Objects.equals(p.second, second);
    }

    @Override
    public int hashCode() {
        return (first == null ? 0 : first.hashCode()) ^ (second == null ? 0 : second.hashCode());
    }

    @Override
    public String toString() {
        return "(" + first + ", " + second + ')';
    }
}

class IntPair extends Pair<Integer, Integer>{
    public IntPair(Integer first, Integer second){
        super(first, second);
    }
}

class LPair extends Pair<Long, Long>{
    public LPair(Long first, Long second){
        super(first, second);
    }
}