You're correct about the "arrays of arrays" part. This is one area of Perl that has been challenging for me. I just need to find time to read through all of the excellent documentation!
]]>1 x_1 y_1
1 x_2 y_2
1 x_3 y_3
like this
Some other people such as Dave Jacoby had examples like this:
where he seemed to think that they were collinear.
]]>https://www.reddit.com/r/perl/comments/koahhf/from_a_reflection_on_the_weekly_challenge_092/
The replies might sound a bit sarcastic but that is because it's actually quite a well-known problem.