h, w = map(int,input().split())
pic = []

kabe_up_down = []
for i in range(w):
    kabe_up_down.append('.')
pic.append(kabe_up_down)

for i in range(h):
    onelist = ['.']
    inp = list(str(input()))
    for mm in range(len(inp)):
        onelist.append(inp[mm])
    onelist.append('.')
    pic.append(onelist)
pic.append(kabe_up_down)    
flag = 1
a = 'a'
for i in range(1,h+1):
    for j in range(1,w+1):
        here = pic[i][j]
        if here =='#' and pic[i+1][j] == '#':
            pic[i][j] = a
            pic[i+1][j] = a
        elif here =='#' and pic[i][j+1] == '#':
            pic[i][j] = a
            pic[i][j+1] = a
        elif here =='#' and pic[i-1][j] == '#':
            pic[i][j] = a
            pic[i-1][j] = a
        elif here =='#' and pic[i][j+1] == '#':
            pic[i][j] = a
            pic[i][j+1] = a    
            
for i in range(1,h+1):
    for j in range(1,w+1):
        here = pic[i][j]
        if here =='#' and pic[i+1][j] == 'a':
            pic[i][j] = a
            pic[i+1][j] = a
        elif here =='#' and pic[i][j+1] == 'a':
            pic[i][j] = a
            pic[i][j+1] = a
        elif here =='#' and pic[i-1][j] == 'a':
            pic[i][j] = a
            pic[i-1][j] = a
        elif here =='#' and pic[i][j+1] == 'a':
            pic[i][j] = a
            pic[i][j+1] = a    
        
        
            
for i in range(1,h+1):
    for j in range(1,w+1):
        if pic[i][j] == '#':
            flag = 0
            break

    
if flag == 0:
    print('No')
else:
    print('Yes')

### FIXED CODE ###

h, w = map(int,input().split())
pic = []

kabe_up_down = []
for i in range(w+2):
    kabe_up_down.append('.')
pic.append(kabe_up_down)

for i in range(h):
    onelist = ['.']
    inp = list(str(input()))
    for mm in range(len(inp)):
        onelist.append(inp[mm])
    onelist.append('.')
    pic.append(onelist)
    
pic.append(kabe_up_down)    


flag = 1
a = 'a'
for i in range(1,h+1):
    for j in range(1,w+1):
        here = pic[i][j]
        if here =='#' and pic[i+1][j] == '#':
            pic[i][j] = a
            pic[i+1][j] = a
        elif here =='#' and pic[i][j+1] == '#':
            pic[i][j] = a
            pic[i][j+1] = a
        elif here =='#' and pic[i-1][j] == '#':
            pic[i][j] = a
            pic[i-1][j] = a
        elif here =='#' and pic[i][j+1] == '#':
            pic[i][j] = a
            pic[i][j+1] = a    
            
for i in range(1,h+1):
    for j in range(1,w+1):
        here = pic[i][j]
        if here == '#' and pic[i+1][j] == 'a':
            pic[i][j] = a
            pic[i+1][j] = a
        elif here =='#' and pic[i][j+1] == 'a':
            pic[i][j] = a
            pic[i][j+1] = a
        elif here =='#' and pic[i-1][j] == 'a':
            pic[i][j] = a
            pic[i-1][j] = a
        elif here =='#' and pic[i][j+1] == 'a':
            pic[i][j] = a
            pic[i][j+1] = a    
        
for i in range(1,h+1):
    for j in range(1,w+1):
        here = pic[i][j]
        if here == a and pic[i+1][j] == '#':
            pic[i][j] = a
            pic[i+1][j] = a
        elif here =='a' and pic[i][j+1] == '#':
            pic[i][j] = a
            pic[i][j+1] = a
        elif here =='a' and pic[i-1][j] == '#':
            pic[i][j] = a
            pic[i-1][j] = a
        elif here =='a' and pic[i][j+1] == '#':
            pic[i][j] = a
            pic[i][j+1] = a            
            
for i in range(1,h+1):
    for j in range(1,w+1):
        if pic[i][j] == '#':
            flag = 0
            

if flag == 0:
    print('No')
else:
    print('Yes')