a,b = map(int,input().split())
c=[list(map(str,list(input()))) for i in range(b)]
#c = list(map(str,input().split()))
# for i in range(len(a)+2):
#     c.insert()
#c[Y][X]
x=a
y=b
e=0
r=0

for i in range(0,y,1):
    for j in range(1,x,1):
        if c[i][j] == "#":
            e+=2
            if i > 0 and i < x-1 and j >0 and j < y-1:
                if c[i+1][j]=="#" or c[i][j+1]=="#" or c[i-1][j]=="#" or c[i][j-1]=="#" :
                    r+=2

            elif i==0 and j!= 0 and j != y-1 :
                if c[i+1][j]=="#" or c[i][j+1]=="#" or c[i][j-1]=="#" :
                    r+=2

            elif i == x-1 and j != 0 and j != y-1 :
                if c[i][j+1] == "#" or c[i-1][j] == "#" or c[i][j-1] == "#" :
                    r+=2

            elif j == 0 and i != 0 and i != y-1:
                if c[i+1][j] == "#" or c[i][j+1] == "#" or c[i-1][j] == "#" :
                    r+=2

            elif j == y-1 and i != y-1 and i != 0:
                if c[i+1][j] == "#" or c[i-1][j] == "#" or c[i][j-1] == "#" :
                    r+=2

            elif i==0 and j == 0:
                if c[i+1][j]=="#" or c[i][j+1]=="#" :
                    r+=1

            elif i==0 and j == y-1:
                if c[i+1][j]=="#"  or c[i][j-1]=="#" :
                    r+=2

            elif i==x-1 and j == 0:
                if c[i][j+1]=="#" or c[i-1][j]=="#" :
                    r+=2

            elif i == x-1 and j == y-1:
                if c[i-1][j]=="#" or c[i][j-1]=="#" :
                    r+=2
if r==e:

    print("Yes")
else :

    print("No")