C#为什么没有适合的方法重写

namespace Shapes
{
using System;

public class Square
{
private int x1,y1,x2,y2,x3,y3;
private float a,b,c;
public Square(int x1,int y1,int x2,int y2, int x3, int y3,float a,float b,float c,float ss,float sss)
{

this.x1 = x1;
this.y1 = y1;
this.x2=y2;
this.y2=y2;
this.x3=y3;
this.y3=y3;
}
public int X1
{
get
{
return x1;
}
set
{
x1 = value;
}
}
public int Y1
{
get
{
return y1;
}
set
{
y1 = value;
}
}
public int X2
{
get
{
return x2;
}
set
{
x2= value;
}
}

public int Y2
{
get
{
return y2;
}
set
{
y2 = value;
}
}