Backyard Ultra, not yet thanks

There is something especially rewarding when I get to run multiple times in a day, perhaps because it feels so "pro" or because I know it improves my overall efficiency and endurance, or maybe just because I get to do more of what I love!
Today, I ended up heading out for a run three times in a day as I needed to take my car to the mechanic. It reminded me of a run I did across Uganda a few years ago. Five of us relayed the length of Uganda in five days, running 5km at a time. Overall, it was a once-in-a-lifetime phenomenal experience, and I quickly found out that running 4x5km with 90 minutes of rest in between is way harder than running 20km in one go.
With that in mind, looking at the Backyard Ultra race format, one must appreciate the amount of grit runners must have to run for 6.7km laps every hour, for up to 90 hours (almost 4 days!) as the current world record stands.
I am not yet interested in taking on the Backyard Ultra; I'll stick to my casual double runs for now, which also drastically reduce the amount of washing I need to do!