Check out one of the best arena for line follower robot, I have seen. These two arenas provide really tough angles and edges, which is very hard to follow by normal line follower robots.
Here is the first one (White board with Black tape arena)
Now the second one (Black board with White tape) more rounds, more angles....
And even for contestants, organizers arranged practice arena too with the same level of toughness. So they can arrange their sensors and motor speed for sharp edges.
Happy Thinking Naturally..........
