construct a peferect Hendecagon

Hendecagon is nonconstructive polygon by compass also. In wiki, there is a method with the central angel error is 0.01°. So accumulated error is about 0.1°.

I had found a very precis method which the central angel error is 0.000026°。 The accumulation error is 0. 00026°，which is nearly perfect for the compass and straight.

And the more interesting is ,when you finish the construction ,the line and arc like paint. see the right picture.

I will not post the details and you can try yourself by stating from the two little squares in the central.

Good Luck and have a fun.