Hopefully you noticed that the two circles stayed congruent, no matter where you dragged the points.  We call this the '[b]drag test[/b]'.  If you make something in GeoGebra and it [b]maintains its characteristics no matter where you drag the points[/b], then it passes the [b]drag test[/b].  See if you can make a square that passes the drag test.  You may use any tool you like.  You have probably noticed that all the tools have instructions that pop up when you click a tool.