w, h = (int(i) for i in input().split())  
s = [[i for i in list(input())] for i in range(w)] 


for i in range(w):
    for j in range(h):
        if s[i][j] == '#':
            if j-1<0 and i+1>=w and j+1>=h:
                if s[i-1][j] == '#' or s[i+1][j] == '#'  or s[i][j+1] == '#':
                    continue
                else:
                    print("No")
                    exit()        
            elif i-1<0 and j-1>=0 and j+1<=h:
                if  s[i+1][j] == '#' or s[i][j-1] == '#' or s[i][j+1] == '#':
                    continue
                else:
                    print("No")
                    exit() 
            elif j-1<0 and i+1>=w and j+1>=h and i-1 >=0:
                if s[i-1][j] == '#' or s[i+1][j] == '#'  or s[i][j+1] == '#':
                    continue
                else:
                    print("No")
                    exit() 
            elif j-1<0 and i+1>=w and j+1>=h and i-1 >=0 :
                if s[i-1][j] == '#' or s[i+1][j] == '#' or s[i][j-1] == '#' or s[i][j+1] == '#':
                    continue
                else:
                    print("No")
                    exit()        

print("Yes")