h, w = map(int, input().split())
a = [list(input()) for _ in range(h)]

for i in range(h):
  for j in range(w):
    if j > 0 and a[i][j-1] != "." and a[i][j] = "#":
      a[i][j] = "*"
    elif j < w - 1 and a[i][j+1] != "." and a[i][j] = "#":
      a[i][j] = "*"
    elif i > 0 and a[i-1][j] != "." and a[i][j] = "#":
      a[i][j] = "*"
    elif i < h - 1 and a[i+1][j] != "." and a[i][j] = "#":
      a[i][j] = "*"

print("No" if sum([row.count("#") for row in a]) else "Yes")
