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import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;

import static java.lang.Long.max;
import static java.lang.Long.toHexString;
import static java.lang.Math.abs;
import static java.lang.Math.sin;


public class B {


    public static void main(String[] args) {

        MyScanner in = new MyScanner();
        int sizeI = in.nextInt();
        int sizeJ = in.nextInt();

        String[] s = new String[sizeI];
        for(int i=0;i<sizeI;++i){
            s[i] = in.next();
        }

        for(int i1=0;i1<sizeI;++i1){
            for(int i2=0;i2<sizeI;++i2){
                for(int j=0;j<sizeJ;++j){
                    if(s[i1].charAt(j)=='#' && s[i2].charAt(j)=='#'){
                        if(!s[i1].equals(s[i2])){
                            System.out.println("No");
                            return;
                        }
                    }
                }
            }
        }

        for(int j1=0;j1<sizeJ;++j1){
            for(int j2=0;j2<sizeJ;++j2){
                for(int i=0;i<sizeI;++i){
                    if(s[i].charAt(j1)=='#' && s[i].charAt(j2)=='#'){
                        String c1 = col(s,j1);
                        String c2 = col(s,j2);
                        if(!c1.equals(c2)){
                            System.out.println("No");
                            return;
                        }
                    }
                }
            }
        }

        System.out.println("Yes");

    }

    static String col(String[] s, int colIndex){
        StringBuffer col = new StringBuffer();
        for(int i=0;i<s.length;++i){
            col.append(s[i].charAt(colIndex));
        }
        return col.toString();
    }




    // -----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

    }
    // --------------------------------------------------------


}
