H,W = map(int,input().split())
s = [list(input()) for i in range(W)]
for i in range(H):
    for j in range(W):
        if s[i][j] == '#':
            if i == 0:
                if j == 0:
                    if s[i+1][j] != '#' and s[i][j+1] != '#':
                        print('No')
                        exit()
                elif j == W-1:
                    if s[i+1][j] != '#' and s[i][j-1] != '#':
                        print('No')
                        exit()
                else:
                    if s[i+1][j] != '#' and s[i][j-1] != '#' and s[i][j+1] != '#':
                        print('No')
                        exit()
            elif i == H-1:
                if j == 0:
                    if s[i-1][j] != '#' and s[i][j+1] != '#':
                        print('No')
                        exit()
                elif j == W-1:
                    if s[i-1][j] != '#' and s[i][j-1] != '#':
                        print('No')
                        exit()
                else:
                    if s[i-1][j] != '#' and s[i][j-1] != '#' and s[i][j+1] != '#':
                        print('No')
                        exit()
            else:
                if j == 0:
                    if s[i-1][j] != '#' and s[i][j+1] != '#' and s[i+1][j] != '#':
                        print('No')
                        exit()
                elif j == W-1:
                    if s[i-1][j] != '#' and s[i][j-1] != '#' and s[i+1][j] != '#':
                        print('No')
                        exit()
                else:
                    if s[i-1][j] != '#' and s[i][j-1] != '#' and s[i][j+1] != '#' and s[i+1][j] != '#':
                        print('No')
                        exit()
print('Yes')

