Rewrite: "Scales are used to map the values of a variable (input) to a visual range (output). This output range often spans the coordinates of the x or y axis, but it can also span a color range."

Should clarify that you have made the domain and the range the same here; could be a confusing example for this reason

what is the domain, what is the range, in the syntax for this example? is it implicit? (I'm used to the syntax where one declares the range explicitly)

I assume that it implicitly links color to fill, but why is not clear

should explain the "scheme" keyword and link to where they can look up other color schemes

Yes for Observable Plot it is implicitly inferred, but I think I should declare it explicitly.

this is a poor choice from a design perspective; I would give this a bad grade. You should color a categorical variable instead, such as the country code

Accidentally resolved the previous comment.

Yes I agree but the only categorical variable here is the name. I will change the dataset for this example.

Note to self: can fork the submissions for checking.

Note to self: remember to record the lab!