H,W = map(int, input().split())
S = [list(input()) for _ in range(H)]

def search(nx,ny):
    if(nx==0 and ny==0):
        if(S[ny][nx]=="#" and S[ny+1][nx]=="." and S[ny][nx+1]=="."):
            return 1
    elif(nx==W-1 and ny==H-1):
        if(S[ny][nx]=="#" and S[ny-1][nx]=="." and S[ny][nx-1]=="."):
            return 1
    elif(nx==0 and ny==H-1):
        if(S[ny][nx]=="#" and S[ny-1][nx]=="." and S[ny][nx+1]=="."):
            return 1
    elif(nx==W-1 and ny==0):
        if(S[ny][nx]=="#" and S[ny+1][nx]=="." and S[ny][nx-1]=="."):
            return 1
    elif(ny==0):
        if(S[ny][nx]=="#" and S[ny][nx-1]=="." and S[ny][nx+1]=="." and S[ny+1][nx]=="."):
            return 1
    elif(nx==0):
        if(S[ny][nx]=="#" and S[ny-1][nx]=="." and S[ny+1][nx]=="." and S[ny][nx+1]=="."):
            return 1
    elif(ny==H-1):
        if(S[ny][nx]=="#" and S[ny][nx-1]=="." and S[ny][nx+1]=="." and S[ny-1][nx]=="."):
            return 1
    elif(nx==W-1):
        if(S[ny][nx]=="#" and S[ny-1][nx]=="." and S[ny+1][nx]=="." and S[ny][nx-1]=="."):
            return 1
    else:
        if(S[ny][nx]=="#" and S[ny][nx-1]=="." and S[ny][nx+1]=="." and S[ny-1][nx]=="." and S[ny+1][nx]=="."):
            return 1
    
    return 0

sum = 0
for i in range(H):
    for j in range(W):
        sum += search(i,j)
        
if(sum==0):
    print("Yes")
else:
    print("No")