public void TestArc()
{
var point1 = Interaction.GetPoint("\nStart");
Draw.Circle(point1, 5);
var point2 = Interaction.GetPoint("\nMid");
Draw.Circle(point2, 5);
var point3 = Interaction.GetPoint("\nEnd");
Draw.Circle(point3, 5);
Draw.Arc3P(point1, point2, point3);
}