随着点的移动，什么保持不变，什么改变？[br] 在此转换过程中，有没有要解决的问题？[br] 坐标（x, y）会映射到哪里？
Explore what happens when you move the points C, D and E then answer the questions below.[br]You can also move the mirror line by moving the big blue dot.
What stays the same and what changes as you move the points around?
Are there any points that do not move under this transformation?
Where would the point [math](x,y)[/math] map to?
[color=#0a971e]Created by N.Trubridge[/color]