yeah - no worries

Nope, no examples, looks like I was mistaken. I was looking at the examples on Desmos which were out of order in some cases.

I modified my code to fix what I thought was the issue, but must have fixed the actual issue accidentally at the same time.

That's just the way codewars is these days - don't want to make ranking up too easy ;)

As for the (0, 0) it should always be in the list - do you have any examples of when it wasn't?
I have moved it to first in the fixed tests.

Feels like it should be ranked higher that 5kyu, but otherwise fun problem.

One thing to note that did mess me up: The kata definition states that the starting point is (0,0), so I don't think that it should be included in the passed list. Or, if it must be passed in the list, it should always be first. A few of the inputs included (0,0) in apparently random places.

(px - a)^2 + (qy - b)^2 = r^2

No, the equation used is slightly different, which is why the way p and q are applied is mentioned in the description. You should be able transform it to the canonical form without any problems if you need to.

Is the equation given for the ellipse correct? It seems like it should be (p(x - a))^2 + (q(y - b))^2 = r^2