A random World Capital has been put in the centre! Below it you are shown, in order, the 4 capital cities that are closest to it when going South (rhombus bearing between 157.5º and 202.5º). To its right, you have the 4 closest capitals cities that are in the East direction; going down and right you have the 4 closest in Southeast direction and so on.
To make sure you really mean to guess the target capital you have to TYPE ITS NAME TWICE! eg if the quiz was about US Capitals and the answer was Boise you'd have to type Boiseboise
If you see that one of the cells that could hold an answer doesn't have a border, it means that there aren't enough capitals in that direction so that cell holds no answer
I was surprised myself to see that Djibouti isn't followed by Sana'a but Sana'a and Riyadh end up being considered in the 'North' direction instead of Northeast and are further away than Asmara so don't appear in the quiz
Also, why should Windhoek and Port Louis be at the end of the line? If you keep going onwards around the globe, you must eventually come to another capital.
because there's only 3 capitals for which the rhombus bearing is the 'Southeast/Southwest' direction. The ones that you'd reach by travelling around the globe are considered in another direction category eg Northwest