# -*- coding: utf-8 -*-

H,W=map(int,input().split())

field=[]
for i in range(H):
    tmp=list(input())
    field.append(tmp)

for i in range(H):
    for j in range(W):
        if field[i][j]=="#"
            check="hoo"
            if i-1>=0 and field[i-1][j]=="#":
                check="hey"
            if j+1<=W and field[i][j+1]=="#":
                check="hey"
            if i+1<=H and field[i+1][j]=="#":
                check="hey"
            if j-1>=0 and field[i][j-1]=="#":
                check="hey"
            if chack=="hoo":
                flag=True
                break
        else:
            continue
    if flag:
        print("No")
        break
if flag!=True:
    print(Yes)