def input():
    import sys
    return sys.stdin.readline().rstrip()


def main():
    import math
    import collections
    import itertools

    h, w = map(int, input().split())
    
    ss = [['.'] * w] + ['.' + input() + '.' for _ in range(h)] + [['.'] * w]

    for i in range(1, h + 1):
        for j in range(1, w + 1):
            if ss[i][j] == '#':
                if ss[i + 1][j] == '.' and ss[i - 1][j] == '.' and ss[i][j + 1] == '.' and ss[i][j - 1] == '.':
                    print("No")
                    break
        else:
            continue
        break
    else:
        print("Yes")



if __name__ == '__main__':
    main()