#!/usr/bin/env python3
import sys

YES = "Yes"  # type: str
NO = "No"  # type: str

def solve(H: int, W: int, s: "List[str]"):

    def get_s(i,j):
        if 0 <= i < H and 0 <= j < W:
            return s[i][j]
        else:
            return "."

    for i in range(H):
        for j in range(W):
            if s[i][j] == "#":
                if  all([get_s(i+di,j+dj) == "." for di,dj in [(1,0),(-1,0),(0,1),(0,-1)]]):
                    print(NO)
                    return

    print(YES)
    return


# Generated by 1.1.4 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    H = int(next(tokens))  # type: int
    W = int(next(tokens))  # type: int
    s = [ next(tokens) for _ in range(W) ]  # type: "List[str]"
    solve(H, W, s)

if __name__ == '__main__':
    main()
