public class HelloWorld
{
  static int[][] arr = new int[4][4];

  public static void main(String[] args)
  {
    arr[0]=new int[]{1,2,3,4};
    arr[1]=new int[]{5,6,7,8};
    arr[2]=new int[]{9,10,11,12};
    arr[3]=new int[]{13,14,15,16};

    int startpos=0;
    int stoppos=arr[0].length;

    while(startpos<stoppos){
    	printrow(startpos,stoppos,startpos,true);
    	printcol(startpos+1,stoppos-1,stoppos,true);
    	printrow(stoppos,startpos,stoppos,false);
    	printcol(stoppos-1,startpos+1,startpos,false);
      	startpos++;
      	stoppos--;
      if(startpos==stoppos){
      	System.out.print(arr[startpos][stoppos]);
        break;
      }
    }
  }

  public static void printrow(int startColumnIndex, int stopColumnIndex, int rowindex,boolean increment){
    for(int i=startColumnIndex;;){
      if(increment){
        if(i<=stopColumnIndex){
        	System.out.print(arr[rowindex][i]+" ");
          i++;
        }else{
        	break;
        }
      }else{
        if(i>=stopColumnIndex){
        	System.out.print(arr[rowindex][i]+" ");
          i--;
        }else{
        	break;
        }
      }
    }
  }


  public static void printcol(int startRowindex, int stopRowindex, int coulumnindex,boolean increment){
    for(int i=startRowindex;;){
      if(increment){
        if(i<=stopRowindex){
        	System.out.print(arr[i][coulumnindex]+" ");
          i++;
        }else{
        	break;
        }
      }else{
        if(i>=stopRowindex){
        	System.out.print(arr[i][coulumnindex]+" ");
          i--;
        }else{
        	break;
        }
      }
    }
  }


}