Copy a Line Segment
Let's start with the simplest construction.
Given a line segment AB, copy it to the dotted line as shown in the applet.
Note: 
is the modern compass and 
is the Euclidean compass. It is pretty easy to do it using modern compass, isn't it?
is the modern compass and is the Euclidean compass. It is pretty easy to do it using modern compass, isn't it?