Here is how you can build the most excellent rectangle ever conceived...
![100_1233](http://static1.squarespace.com/static/5b50dee412b13f916dbf6993/5b64a7fce0c9380bf64954f1/5b64a804e0c9380bf6495686/1533323268186/100_1233.jpg?format=original)
You start with a square, and you use one edge center point as a centroid of the quarter circle as shown above. Then you can trace on top of this rectangle spiral growth rings...
![100_1232](http://static1.squarespace.com/static/5b50dee412b13f916dbf6993/5b64a7fce0c9380bf64954f1/5b64a804e0c9380bf6495688/1533323268223/100_1232.jpg?format=original)