import sys
h,w = map(int,input().split())
matrix = [[0]*(h+2) for _ in range(w+2)]
for hi in range(h):
    all_inp = input()
    for i,a in enumerate(all_inp):
        matrix[hi+1][i+1]= 0 if a == '.' else 1
#print(matrix)
for ri,row in enumerate(matrix):
    for ci,column in enumerate(row):
        if column == 1:
            if row[ci-1] == 0 and row[ci+1] == 0 and matrix[ri-1][ci] == 0 and matrix[ri+1][ci] == 0:
                print('No')
                sys.exit()
print('Yes')