You guys are geniuses! How do you do it?

The point in the description is not to show all the steps in a recursion, but to show how the rules can be used to determine the values of the function. You can use recursion, but that's up to you. It's also your job to figure out why and how one could use recursion.

I believe there is an error in the example portion of your intructions that lends to some confusion.

Current:
"Putting these results together fusc(10) = fusc(5) = fusc(2) + fusc(3) = 1 + 2 = 3"

Should be:
"Putting these results together fusc(10) = fusc(5) = fusc(2) + fusc(3) = 1 + fusc(1) + fusc(2) = 1 + 1 + 1 = 3"

Even more accurately:
"Putting these results together fusc(10) = fusc(5) = fusc(2) + fusc(3) = fusc(1) + fusc(1) + fusc(2) = 1 + 1 + fusc(1) = 1 + 1 + 1 = 3"

The example should show all the steps of recursion. Currently it appears that fusc(3) directly equals 2 when actually there's another step of recursion that further expands fusc(3) into 2 more functions. I think it's important to show this extra step for clarity.

can't do anything with this issue since it doesn't provide a way to reproduce the problem
(also I'm struggling to understand what the problem is here)

your class should raise an exception when the input isn't a valid kata rank. doesn't matter whether or not your user rank is already 8.