And so we continue…
If we swing the diagonal of the √3 rectangle we make a √4 rectangle. The √4 = 2 so the ratio of the √4 is 1:2. Diagrams 1 & 2
![Root-4-Construction](http://howartworks.com/wp-content/uploads/2017/11/Root-4-Construction.jpg)
![Root-4-Origins](http://howartworks.com/wp-content/uploads/2017/11/Root-4-Origins.jpg)
The √4 rectangle can be divided into:
4) √4 rectangles- Diagram 3
![R4-Rectangle](http://howartworks.com/wp-content/uploads/2017/11/R4-Rectangle.jpg)
(2) equal squares- Diagram 4
![](http://howartworks.com/wp-content/uploads/2017/11/Root-4-2-Squares.jpg)
A square centered on the √4 rectangle with flanking √4 rectangles on either side- Diagram 5
![R4-Center-Square](http://howartworks.com/wp-content/uploads/2017/11/R4-Center-Square.jpg)
The √4 is the only other rational rectangle after the square as it is (2) squares.
Modern construction materials like masonry units, sheathing and wall board are based on the √4 rectangle.
The examples below show Da Vinci*, Uglow and Hockney using the √4 rectangle. Diagram 6
![](http://howartworks.com/wp-content/uploads/2017/11/Root-4-Examples-2-1.jpg)
We will look at each of these in more depth later…
* ‘The Last Supper’ has a surprising structure.