Flying back home from Costa Rica. Right now, we are over Nicaraguan territory. Directly below us – if you see the picture below – is an island. If you carefully notice, it is actually a volcano – Volcan Maderas is the local name. The waterbody around it that you can see is Lake Nicaragua (Lago Cocibolca is the local name). If you carefully follow the volcano contours, you can see the crater – unfortunately, from my angle, it is somewhat covered by a cloud. In any case, the crater is filled with water and is a lake itself. If you zoom that area, you will see a dark shaded area around the light shaded cloud shadow. I do not know the name of that lake. But that lake is a “recursive” lake.

It is a lake in an island which is in a lake!!

For the math geeks – the longest recursion is in the Philippines. Imagine what you are seeing here… just that there is a small island within the crater. And remember, the Philippines is an archipelago. So, you have an island in a lake in an island in a lake in an island!!

For the non-math geeks, understanding recursion is easy. First you understand recursion, then the rest is easy!!