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

for i in range(h):
    for j in range(w):
        if m[i][j] == '#':
            if 0 < i <= h and 0 < j <= w:
                cnt = 4
            else:
                cnt = 3
            # up
            if 0 <= i-1:
                if m[i-1][j] != '#':
                    cnt -= 1

            # down
            if i+1 < h:
                if m[i+1][j] != '#':
                    cnt -= 1
            # left
            if 0 >= j-1:
                if m[i][j-1] != '#':
                    cnt -= 1

            # right
            if j+1 < w:
                if m[i][j+1] != '#':
                    cnt -= 1

            if cnt == 0:
                print('No')
                exit(0)
else:
    print('Yes')
