import sys

# sys.setrecursionlimit(200005)
# sys.set_int_max_str_digits(1000005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = -1-(-1 << 63)
# md = 10**9+7
md = 998244353

h,w=LI()
k=II()

tt=[[[-1]*4 for _ in range(w)] for _ in range(h)]
tt[0][0][3]=0
i,j,dir=0,0,3
last=-1
for t in range(k-1):
    di=1 if dir&1 else -1
    dj=1 if dir&2 else -1
    if 0<=i+di<h:
        i+=di
    else:
        dir^=1
    if 0<=j+dj<w:
        j+=dj
    else:
        dir^=2
    if tt[i][j][dir]==-1:
        tt[i][j][dir]=t+1
    else:
        last=t+1
        break
# p2D(tt)
# pDB(i,j,dir,last)

if last==-1:
    for i in range(h):
        s=[]
        for j in range(w):
            if tt[i][j].count(-1)&1:
                s.append("#")
            else:
                s.append(".")
        print(*s,sep="")
else:
    p,r=divmod(k,last)
    # pDB(p,r)
    p&=1
    for i in range(h):
        s=[]
        for j in range(w):
            c=0
            for dir in range(4):
                if tt[i][j][dir]==-1:continue
                if tt[i][j][dir]<r:
                    c^=p^1
                else:
                    c^=p
            if c:
                s.append("#")
            else:
                s.append(".")
        print(*s,sep="")