import sys
input = sys.stdin.readline

H,W=map(int,input().split())
grid = [list(input().rstrip()) for _ in range(H)]
for i in range(H):
  for j in range(W):
    if j > 0 and grid[i][j-1] != '.' and grid[i][j] == '#':
      grid[i][j] = '*'
    elif j < W-1 and grid[i][j+1] != '.' and grid[i][j] == '#':
      grid[i][j] = '*'
    elif i > 0 and grid[i-1][j] != '.' and grid[i][j] == '#':
      grid[i][j] = '*'
    elif i < H-1 and grid[i+1][j] != '.' and grid[i][j] == '#':
      grid[i][j] = '*'
print("No" if sum([row.count('*') for row in grid]) else "Yes")      