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import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

public class C2403201801 {

  private static void solve(final Input input, final PrintWriter output) throws IOException {
    int rows = input.nextInt();
    int cols = input.nextInt();
    char[][] array = new char[rows][cols];
    for (int i = 0; i < rows; i++)
      array[i] = input.next().toCharArray();
    Map<Integer, Set<Integer>> map = new HashMap<>();
    for (int row = 0; row < rows; row++) {
      for (int col = 0; col < cols; col++) {
        if (array[row][col] == '#') {
          map.compute(row, (k, v) -> v == null ? new HashSet<>() : v).add(col);
        }
      }
    }

    for (Map.Entry<Integer, Set<Integer>> entry : map.entrySet()) {
      for (Map.Entry<Integer, Set<Integer>> sentry : map.entrySet()) {
        if (sentry.getKey() == entry.getKey())
          continue;
        Set<Integer> aset = new HashSet<>(sentry.getValue());
        aset.addAll(entry.getValue());
        if (sentry.getValue().size() + entry.getValue().size() != aset.size()) {
          if (entry.getValue().size() != aset.size() || sentry.getValue().size() != aset.size()) {
            System.out.println("No");
            return;
          }
        }
      }
    }
    System.out.println("Yes");
    return;
  }

  public static void main(String[] args) throws IOException {
    try (final PrintWriter output = new PrintWriter(System.out);
        final Input input = new Input(new BufferedReader(new InputStreamReader(System.in)))) {
      solve(input, output);
    }
  }

  private static class Input implements Closeable {

    private final BufferedReader bufferedReader;
    private final StringBuilder stringBuilder = new StringBuilder();
    private final static char[] SEPERATOR = { '\t', '\n', '\r', ' ' };

    public Input(final BufferedReader in) {
      this.bufferedReader = in;
    }

    private boolean isAnySeperator(final char ch) {
      return ch == SEPERATOR[3] || ch == SEPERATOR[1] || ch == SEPERATOR[0] || ch == SEPERATOR[2];
    }

    private boolean isLineSeperator(final char ch) {
      return ch == SEPERATOR[1] || ch == SEPERATOR[2];
    }

    public String next() throws IOException {
      stringBuilder.setLength(0);
      while (true) {
        int c = bufferedReader.read();
        if (c == -1) {
          return null;
        }
        char ch = (char) c;
        if (!isAnySeperator(ch)) {
          stringBuilder.append(ch);
          break;
        }
      }
      while (true) {
        int c = bufferedReader.read();
        char ch = (char) c;
        if (c == -1 || isAnySeperator(ch)) {
          break;
        }
        stringBuilder.append(ch);
      }
      return stringBuilder.toString();
    }

    public String nextLine() throws IOException {
      stringBuilder.setLength(0);
      while (true) {
        final int c = bufferedReader.read();
        if (c == -1) {
          return null;
        }
        final char ch = (char) c;
        if (!isLineSeperator(ch)) {
          stringBuilder.append(ch);
          break;
        }
      }
      while (true) {
        int c = bufferedReader.read();
        char ch = (char) c;
        if (c == -1 || isLineSeperator(ch)) {
          break;
        }
        stringBuilder.append(ch);
      }
      return stringBuilder.toString();
    }

    public int nextInt() throws IOException {
      return Integer.parseInt(next(), 10);
    }

    public long nextLong() throws IOException {
      return Long.parseLong(next(), 10);
    }

    @Override
    public void close() throws IOException {
      bufferedReader.close();
    }
  }
}