import sys

input = sys.stdin.readline

d = '.'
dn = '#'

def isPaintable(h, w, x, y, canvas):
    ret = False
    if x > 0:
        if canvas[x-1, y] == dn:
            ret = True
    elif x < w:
        if canvas[x+1, y] == dn:
            ret = True
    elif y > 0:
        if canvas[x, y-1] == dn:
            ret = True
    elif y < h:
        if canvas[x, y+1] == dn:
            ret = True
    return ret

def main():
    ans = 'Yes'
    h, w = map(int, input().split())
    canavs = []
    for _ in range(h):
        s = list(input().split().rstrip('\n'))
        canvas.append(s)
    for i in h:
        if ans == 'No':
            break
        for j in w:
            if not isPaintable(h, w, j, i, canvas):
                ans = 'No'
                break
    print(ans)

if __name__ == '__main__':
    main()