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()
x=a
y=b
e=0
r=0
for i in range(x):
    for j in range(y):
        if c[i][j] == "#":
            e+=1
            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+=1

            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+=1

            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+=1

            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+=1

            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+=1

            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+=1

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

            elif i==x-1 and j == y<-1:
                if c[i-1][j]=="#" or c[i][j-1]=="#" :
                    r+=1
if r==e:
    print("Yes")
else :
    print("No")
