H, W = map(int, input().split())
grid = [0]*H
for i in range(H):
    grid[i] = input()

ans = 1
for h in range(H):
    for w in range(W):
        if ans == 0:
            break
        if grid[h][w] == "#":
            if h == 0:
                if w == 0:
                    if grid[h + 1][w] == "." and grid[h][w+1] == ".":
                        ans = 0
                elif w == W - 1:
                    if grid[h + 1][w] == "." and grid[h][w-1] == ".":
                        ans = 0
                elif grid[h + 1][w] == "." and grid[h][w - 1] == "." and grid[h][w + 1] == ".":
                    ans = 0
            elif h == H - 1:
                if w == 0:
                    if grid[h - 1][w] == "." and grid[h][w+1] == ".":
                        ans = 0
                elif w == W - 1:
                    if grid[h - 1][w] == "." and grid[h][w-1] == ".":
                        ans = 0
                elif grid[h - 1][w] == "." and grid[h][w - 1] == "." and grid[h][w + 1] == ".":
                    ans = 0
            elif w == 0:
                if grid[h - 1][w] == "." and grid[h][w+1] == "."and grid[h + 1][w] == ".":
                    ans = 0
            elif w == W - 1:
                if grid[h - 1][w] == "." and grid[h][w-1] == "."and grid[h + 1][w] == ".":
                    ans = 0
            elif grid[h - 1][w] == "." and grid[h][w - 1] == "." and grid[h][w + 1] == "." and grid[h - 1][w] == ".":
                ans = 0

if ans == 1:
    print("Yes")
else:
    print("No")
