import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const M = readInt;
      const N = readInt;
      const K = readLong;
      
      auto vis = new int[2][2][][](M, N);
      foreach (x; 0 .. M) foreach (y; 0 .. N) {
        static foreach (s; 0 .. 2) static foreach (t; 0 .. 2) {
          vis[x][y][s][t] = -1;
        }
      }
      int L, R;
      int[] xs, ys;
      for (int i = 0, x = 0, y = 0, s = 0, t = 0; ; ++i) {
        xs ~= x;
        ys ~= y;
        if (~vis[x][y][s][t]) {
          L = vis[x][y][s][t];
          R = i;
          break;
        }
        vis[x][y][s][t] = i;
        if (s) {
          (x - 1 >= 0) ? --x : (s ^= 1);
        } else {
          (x + 1 < M) ? ++x : (s ^= 1);
        }
        if (t) {
          (y - 1 >= 0) ? --y : (t ^= 1);
        } else {
          (y + 1 < N) ? ++y : (t ^= 1);
        }
      }
      debug {
        writefln("L = %s, R = %s", L, R);
      }
      
      auto a = new int[][](M, N);
      if (K < L) {
        foreach (i; 0 .. K) a[xs[i]][ys[i]] ^= 1;
      } else {
        foreach (i; 0 .. L) a[xs[i]][ys[i]] ^= 1;
        const quo = (K - L) / (R - L);
        const rem = (K - L) % (R - L);
        if (quo & 1) foreach (i; L .. R) a[xs[i]][ys[i]] ^= 1;
        foreach (i; L .. L + rem) a[xs[i]][ys[i]] ^= 1;
      }
      
      foreach (x; 0 .. M) {
        foreach (y; 0 .. N) write(".#"[a[x][y]]);
        writeln;
      }
    }
  } catch (EOFException e) {
  }
}