iSetSquare is a free Android app developed by plaincode that helps you draw geometry exact figures on paper using your phone. It can also be used in physiotherapy to measure movement angles. The app uses the gyroscope sensor features to work as a goniometer tool and measure relative angles and rotation counter. It offers 5 unit modes that can be quickly switched, and the display can be set to either background or foreground rotation. The gyrometer can be finely calibrated, and the app offers both motion-sensitive and manual lock mode options. Additionally, it comes with a scrollable ruler that can be set to inch or cm. Overall, iSetSquare is an excellent app that performs its intended functions with ease and is a must-have for anyone who needs to measure angles or draw geometry figures.