h,w = map(int,input().split())
c = [[] for i in range(0,h+2)]
ans = "Yes"
c[0] = ["#"for i in range(0,w+2)]
c[h+1] = ["#"for i in range(0,w+2)]
for i in range(1,h+1):
    d = []
    d = list(input())
    d.append("#")
    d.insert(0,"#")
    c[i] = d
for i in range(1,h+1):
    for j in range(1,w+1):
        if c[j][i] == "#":
            flag = "No"
            if(c[j][i-1] == "#"):
                flag = "Yes"
            if(c[j][i+1] == "#"):
                flag = "Yes"
            if(c[j-1][i] == "#"):
                flag = "Yes"
            if(c[j+1][i] == "#"):
                flag = "Yes"
            if(flag == "No"):
                ans = "No"
print(ans)
