Fix: fixed error messages in lesson 20 part 2

[mstphayassin]

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Related issue (if applicable):

Close #1126
Close #1114
Close #867

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[NathanLovato]

Great catch, thank you very much!

[NathanLovato]

Actually, this caused a regression in other practices, so I'll revert this one.

[NathanLovato]

This is a slightly tricky issue because this turtle does not only draw polygons, but we also need to account for its current state in the practice, like where it's facing. So if we just close the polygon when moving forward, the turtle may not have done a full drawing turn and returned to its original state of facing right or up or something like that which is something we want to check.

I really appreciate you taking a stab at this. I should have just checked more carefully before merging.

Generally speaking, the app and the program could have really used a refactor and thorough integration testing and the likes, though I think someday we'll simply replace it with something new.

I've drafted a new attempt at a fix that delays closing the shape after turns: #1151

It still needs a little work to account for the turtle changing position though, as students sometimes move the turtle without using the jump() function.

[mstphayassin]

Understood, sorry about that. I did some testing in other practices with this solution and didn't see any issues, but I'm glad you caught this. Your solution looks interesting. I might look through it later and see if I can write that last piece. Thanks for the kind words, I'm just glad to help!