Do you believe me when you draw a vertical line?
Specific practices:
1. Make a circle (arc) at point B, and intersect with points AB and BC at points E and F respectively.
2. Make a circle (arc) with the same radius on E and F (the radius is larger, otherwise it will not be handed in later), cross at G point, connect BG and extend.
3. Make a circle (arc) at point C, and hand BC and CD to H and I respectively.
4. Make a circle (arc) with the same radius on H and I (the radius is larger, otherwise it will not be handed in later), cross at J, connect CJ and extend.
5. The intersection of 5.CJ and BG is the point P to be done.