My elementary school(grade 4-6) best friend and junior high best friend became best friends in high school and college!

My definition of "best friend" is a friend you hang out with the most during a period of time, not necessarily always being your closest friend throughout. I grew up in WuHan, one of the most populated cities in China. I went to two different schools from grade 4-9. Grade 4-6 I was in Huaao and grade 7-9 I was in Huayi. Those were boarding schools, they weren't close to each other and students were from all over the city. Wherever I was, there was always one friend that I spent the most time with. It's probably because we had something in common, either we liked the same music or movie, stuff like that (It could also be the fact that we were cool and cool people hang out together, at least that's what we thought). In Huaao it was Lee and in Huayi it was Long. Although we're best friends, we're are terrible at keeping in touch with each other. After I left Huao and went to Huayi, Lee and I couldn't really get a hold of each other and never hung out again throughout junior high. Long was my best friend at the time and we hung out a lot until I moved to California to go to high school there. Also, Long and I could no longer get a hold of each other. Long story short, Lee and Long ended up going to the same high school and became bros. They even went to the same college for a year or two. I think we might be embarrassed to call each other best friend all the time, we're definitely bros for life. It's the type of friends you could only count them in one hand. The interesting thing was the whole time they had no idea they both knew me until like their last year in college. A couple of years after college three of us finally met again, and yes, lots of alcohol was consumed that night. Now we still try to hang out whenever we can. Now let's put things into perspective: What made it probable: 1. Both my elementary school and junior high school were boarding schools, there weren't many boarding schools in that city at the time. 2. I tend to kick it with an older crowd to make me seem more sophisticated. They were both the oldest kids in the class, it was probably natural for them to start to hang out later on since they about the same age. What made it not probable: 1. There were many different schools. 2. There were many different classes. 3. There were many different students in each class.