#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
using namespace std;char mp[20][20];
int n,tot;
int col[4];
bool OK(int x,int y) { return x >= 0 && x < n && y >= 0 && y < n; }
bool findcolor(int i,int j,char ch) {memset(col,0,sizeof(col));if(OK(i+1,j+1) && mp[i+1][j+1] != '.') col[mp[i+1][j+1]-'A']++;if(OK(i+1,j-1) && mp[i+1][j-1] != '.') col[mp[i+1][j-1]-'A']++;if(OK(i-1,j-1) && mp[i-1][j-1] != '.') col[mp[i-1][j-1]-'A']++;if(OK(i-1,j+1) && mp[i-1][j+1] != '.') col[mp[i-1][j+1]-'A']++;for(int k=j-1;k<=j+1;k++) if(OK(i+2,k) && mp[i+2][k] != '.') col[mp[i+2][k]-'A']++;for(int k=i-1;k<=i+1;k++) if(OK(k,j+2) && mp[k][j+2] != '.') col[mp[k][j+2]-'A']++;for(int k=j-1;k<=j+1;k++) if(OK(i-2,k) && mp[i-2][k] != '.') col[mp[i-2][k]-'A']++;for(int k=i-1;k<=i+1;k++) if(OK(k,j-2) && mp[k][j-2] != '.') col[mp[k][j-2]-'A']++;if(col[ch-'A']) return true;return false;
}
void color(int i,int j,char ch) {mp[i][j] = mp[i-1][j] = mp[i][j+1] = mp[i+1][j] = mp[i][j-1] = ch;
}
struct node {int x,y;node(int _x,int _y):x(_x),y(_y){}node(){}
}p[255];bool dfs(int c) {if(c == tot) return true;c++;int x = p[c].x, y = p[c].y;for(int i=1;i<=3;i++) {   //B,C,Dif(!findcolor(x,y,'A'+i)) {    //周边有没有'A'+i这种颜色color(x,y,'A'+i);if(dfs(c)) return true;color(x,y,'.');}}return false;
}int main()
{int t,cs = 1,i,j,k,h;scanf("%d",&t);while(t--){scanf("%d",&n);int space = 0;for(i=0;i<n;i++)scanf("%s",mp[i]);int flag = 1;tot = 0;for(i=0;i<n;i++) {for(j=0;j<n;j++) {if(mp[i][j] == '.') {for(k=j-1;k<=j+1;k++) {if(!OK(i+1,k) || mp[i+1][k] != '.') { flag = 0; break; }else mp[i+1][k] = '#';}if(!OK(i+2,j) || mp[i+2][j] != '.') { flag = 0; break; }else mp[i+2][j] = '#';p[++tot] = node(i+1,j);   //着色中心点
                }}}printf("Case %d:",cs++);if(!flag) { puts(" Not Possible!"); continue; }if(dfs(0)) {puts("");for(i=0;i<n;i++){for(j=0;j<n;j++)printf("%c",mp[i][j]);puts("");}}else puts(" Not Possible!");}return 0;
}