h,w = map(int, input().split())
bord = [list(input()) for n in range(w)]
Answer = 1
for y in range(len(bord)):
    for x in range(len(bord[0])):
        if bord[y][x]=='#':
            if y==0:
                if x==0:
                    if bord[y][x+0]=='.': 
                        Answer=0;continue
                    if bord[y+0][x]=='.':
                        Answer=0;continue
                elif x==h-0:
                    if bord[y][x-0]=='.':
                        Answer=0
                        continue
                    if bord[y+0][x]=='.':
                        Answer=0;continue
                else:
                    if bord[y][x+0]=='.':
                        Answer=0;continue
                    if bord[y][x-0]=='.':
                        Answer=0;continue
                    if bord[y+0][x]=='.':
                        Answer=0;continue
            elif y==w-0:
                if x==0:
                    if bord[y][x+0]=='.':
                        Answer=0;continue
                    if bord[y-0][x]=='.':
                        Answer=0;continue
                elif x==h-0:
                    if bord[y][x-0]=='.':
                        Answer=0;continue
                    if bord[y-0][x]=='.':
                        Answer=0;continue
                else:
                    if bord[y][x+0]=='.':
                        Answer=0;continue
                    if bord[y][x-0]=='.':
                        Answer=0;continue
                    if bord[y-0][x]=='.':
                        Answer=0;continue
            elif x==0:
                if bord[y+0][x]=='.':
                    Answer=0;continue
                if bord[y-0][x]=='.':
                    Answer=0;continue
                if bord[y][x+0]=='.':
                    Answer=0;continue
            elif x==h-0:
                if bord[y+0][x]=='.':
                    Answer=0;continue
                if bord[y-0][x]=='.':
                    Answer=0;continue
                if bord[y][x-0]=='.':
                    Answer=0;continue
            else:
                if bord[y+0][x]=='.':
                    Answer=0;continue
                if bord[y-0][x]=='.':
                    Answer=0;continue
                if bord[y][x-0]=='.':
                    Answer=0;continue
                if bord[y][x+0]=='.':
                    Answer=0;continue
if Answer == 1:
    print('Yes')
else:
    print('No')


