A free program for Android, by Simcoach Games.

This app is designed for construction workers to learn the different hand signals that are used by cranes to communicate while operating heavy equipment. There are 23 different signs to know, and you need to be able to recognize them correctly in order to complete your tasks. You can also get feedback on the signs you missed, and review them in the reference section of the application. If you get a perfect score, you can generate a certificate of completion!

How to play:

In order to play, you need to tap on the screen to choose the right answer. You need to tap on the screen to see the correct sign.