Your post above looks as though it is a somewhat scrambled version of my previous post. But as I read the original question, it wants the mathematical results translated into descriptions in terms of the hypothesized roads and needs to distinguish between the double intersections that do and do not join the two curved roads.
This is actually a very clever exercise. A person who is good at mathematics can analyze problems, but such a person must usually also be good at explaining what the mathematical results mean for the mathematics to bear practical fruit.
This is actually a very clever exercise. A person who is good at mathematics can analyze problems, but such a person must usually also be good at explaining what the mathematical results mean for the mathematics to bear practical fruit.