#include <iostream>
#include <string>
#include <cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<iomanip>
#define _USE_MATH_DEFINES
#include <math.h>
#include <functional>
#include<complex>
using namespace std;

#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)

typedef long long ll;
const ll INF = 1e17;
const ll MOD = 1000000007;
const ll MAX = 4000001;
const long double eps = 1E-14;

ll max(ll a, ll b) {
	if (a > b) { return a; }
	return b;
}

ll min(ll a, ll b) {
	if (a > b) { return b; }
	return a;
}

ll gcd(ll a, ll b) {
	if (b == 0) { return a; }
	if (a < b) { return gcd(b, a); }
	return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

struct edge {
	ll ind;
	ll fr;
	ll to;
	ll d;
};

class mint {
	long long x;
public:
	mint(long long x = 0) : x((x% MOD + MOD) % MOD) {}
	mint operator-() const {
		return mint(-x);
	}
	mint& operator+=(const mint& a) {
		if ((x += a.x) >= MOD) x -= MOD;
		return *this;
	}
	mint& operator-=(const mint& a) {
		if ((x += MOD - a.x) >= MOD) x -= MOD;
		return *this;
	}
	mint& operator*=(const  mint& a) {
		(x *= a.x) %= MOD;
		return *this;
	}
	mint operator+(const mint& a) const {
		mint res(*this);
		return res += a;
	}
	mint operator-(const mint& a) const {
		mint res(*this);
		return res -= a;
	}
	mint operator*(const mint& a) const {
		mint res(*this);
		return res *= a;
	}

	mint pow(ll t) const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}

	// for prime MOD
	mint inv() const {
		return pow(MOD - 2);
	}
	mint& operator/=(const mint& a) {
		return (*this) *= a.inv();
	}
	mint operator/(const mint& a) const {
		mint res(*this);
		return res /= a;
	}

	friend ostream& operator<<(ostream& os, const mint& m) {
		os << m.x;
		return os;
	}
};

mint pw(mint a, ll b) {
	if (b == 0) { return 1; }
	mint ret = pw(a, b >> 1);
	ret *= ret;
	if (b & 1) { ret *= a; }
	return ret;
}

typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;

typedef vector<mint> vmint;
typedef vector<vector<mint>> vvmint;
typedef vector<vector<vector<mint>>> vvvmint;

/////////////////////////////////////


int main() {
	ll H, W, K;
	cin >> H >> W >> K;

	vector<vector<char>> s(H + 1, vector<char>(W + 1));
	repn(i, H)repn(j, W)cin >> s[i][j];

	ll b = 0;
	repn(i, H)repn(j, W) {
		if (s[i][j] == '#') { b++; }
	}

	vll a(2, 0), c(2, 0);

	repn(j, W) {
		if (s[1][j]=='#'&&s[H][j]=='#') { a[0]++; }
	}
	repn(i, H) {
		if (s[i][1] == '#' && s[i][W] == '#') { a[1]++; }
	}

	repn(i, H - 1)repn(j, W) {
		if (s[i][j] == '#' && s[i + 1][j] == '#') { c[0]++; }
	}
	repn(i, H)repn(j, W - 1) {
		if (s[i][j] == '#' && s[i][j + 1] == '#') { c[1]++; }
	}

	if (K == 0) { cout << 1 << endl; }

	//cout << a[0] << a[1] << c[0] << c[1] << endl;

	if (a[0] == 0 && a[1] == 0) {
		cout << pw(b, K-1) << endl;
		return 0;
	}
	if (a[0] != 0 && a[1] != 0) {
		cout << 1 << endl;
		return 0;
	}
	
	ll t = 0;
	if (a[1] != 0) { t = 1; }

	mint X = K-1;
	if (a[t] != b) {
		X = (pw(b, K-1) - pw(a[t], K-1)) / (b - a[t]);
	}

	mint ans = pw(b, K-1) - X * c[t];
	cout << ans << endl;
}


Measured memory_bytes: 4648