Problem 4:
Given a point $A$, a point $B$ and a point $M_{b}$, construct the triangle ABC.

Construction: 
1. Using the point $A$ and the point $M_{b}$, construct a point $C$ (rule W01);
2. Using the point $C$ and the point $A$, construct a point $\_M_{b}$ (rule W01);

Statement:
Prove that the point $B$ is identical to the point $B$.

