H,W=map(int,input().split())
s=[list(input()) for i in range (H)] 
import sys
for j in range (1,W):
    for k in range (1,H-1):
        if s[j][k]=='#' and s[j][k-1]=='.' and s[j][k+1]=='.' and s[j-1][k]=='.' and s[j+1][k]=='.':
            print ('No')
            sys.exit()

#４枠の処理
for j in range (1,H-1):
    if s[j][0]=='#'  and s[j-1][0]=='.' and s[j+1][0]=='.' and  s[j][1]=='.':
        print ('No')
        sys.exit()
    if s[j][W-1]=='#'  and s[j-1][W-1]=='.' and s[j+1][W-1]=='.' and  s[j][W-2]=='.':
        print ('No')
        sys.exit()
        
for j in range (1,W-1):
    if s[0][j]=='#'  and s[0][j-1]=='.' and s[0][j+1]=='.' and  s[1][j]=='.':
        print ('No')
        sys.exit()
    if s[W-1][j]=='#'  and s[W-1][j-1]=='.' and s[W-1][j+1]=='.' and  s[W-2][j]=='.':
        print ('No')
        sys.exit()

if s[0][0]=='#' and s[1][0]=='.' and s[0][1]=='.':
    print ('No')
    sys.exit()
if s[H-1][0]=='#' and s[H-2][0]=='.' and s[H-1][1]=='.':
    print ('No')
    sys.exit()
if s[0][W-1]=='#' and s[1][W-1]=='.' and s[0][W-2]=='.':
    print ('No')
    sys.exit()
if s[H-1][W-1]=='#' and s[H-2][W-1]=='.' and s[H-1][W-2]=='.':
    print ('No')
    sys.exit()

print ('Yes')