Dividing the portrait into pieces
1) Go to https://www.imgonline.com.ua/eng/cut-photo-into-pieces.php
for cutting your photo into 9 square pieces (or more)
2) Download the zip file into your computer.
The images need to be moved to another folder after downloaded in the zip folder.
3) Open GeoGebra at https://www.geogebra.org/classic
