public override bool IsExisting()
{
var points = GetPoints();
for (int i = 0; i < points.Length; i++)
{
var angle = GeometryMath.FindAngle(
new LineSegment(points[i], points[(i + 1) % points.Length]),
new LineSegment(points[(i + 1) % points.Length], points[(i + 2) % points.Length])
);
if (GeometryMath.IsDoubleEqual(angle, System.Math.PI / 2) == false)
{
return(false);
}
}
return(true);
}