h,w = map(int,input().split())
s = [["."]+list(input())+["."] for i in range(h)]

for i in range(h):
  for j in range(1,w+1):
    if i == 0:
      if s[i][j]=="#" and s[i][j+1]=="." and s[i][j-1]=="." and s[i+1][j]==".":
        print("No")
        exit()
    elif i == h-1:
      if s[i][j]=="#" and s[i][j+1]=="." and s[i][j-1]=="." and s[i+1][j]==".":
        print("No")
        exit()
    else:
      if s[i][j]=="#" and s[i][j+1]=="." and s[i][j-1]=="." and s[i+1][j]=="." and s[i-1][j]==".":
        print("No")
        exit()
        
print("Yes")
      