Update README.md

README.md

@@ -2,6 +2,9 @@
 
 A competitive game in groups with Thymio.
 
+The teams have to create a program to reach the goal as fast as possible while 
+avoiding obstacles. 
+
 ## Running the game
 
 The game needs at least Python 3.6.
@@ -27,6 +30,10 @@ Print the tags provided in [apriltags.pdf](apriltags.pdf) and put a tag on each
 Thymio with the corresponding color. The activity is meant to be used with VPL,
 or the automated start won't work.
 
+It is also necessary to prepare the ground for the race, the ideal would be to have
+a start line where the Thymios can be positioned, a finish line, and a path with 
+curves and obstacles in between.
+
 ## Choosing a webcam
 
 The first window opened gives you the ability to choose one of your available