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No
 No
 No
 Yes
 Yes
 No
 Yes
 Yes
 Yes
 No
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 No
 No

aa = (input()).split()
xx = int(aa[0])
yy = int(aa[1])
dd = [0] * yy
prime=[2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,397,401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,503,509,521,523,541,547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,641,643,647,653,659]
fflag = 0
for i in range (0,xx):
    ss= input()

    ll= []
    flag = 0
    for j in range(0, len(ss)):
        if ss[j]=='#':
            ll.append(j)

            if dd[j]>0:
                flag=1
    if flag == 0:
        mul = 0
        for j in range(0,len(ll)):
            dd[ll[j]]=i+1
    else:
        max = dd[ll[0]]
        for j in range(0, len(ll)):
            temp = dd[ll[j]]
            if temp!=max:
                print("No")
                fflag = 1
                break
            else:
                for k in range(0,yy):
                    if dd[k]==temp:
                        if k not in ll:
                            print("No")
                            fflag =1
                            break
            if fflag==1:
                break
    if fflag==1:
        break
if fflag==0:
    print("Yes")


