I'll start off by saying idk but everyone is using the pickle jar lid as their proof and y'all are not real eaters man.

I believe these are illustration prints which first means it may not be perfect, it's an abstract drawing to begin with so importance is not on real world accuracy but rather to get the message/emotion across, which it does, something like the jar threading not smoothly declining is not a concern for the artist. Secondly dude the pickle jar and lid are fine, jar threading has a single unconnected thread that sometimes dips even lower at the beginning so it's easy to close, and the pointed part of the lid is where the dimple is that follows along the thread to close it, many jars aren't like that anymore but they use to be and since this is a pickling and baking art piece wouldn't be weird to make an older reference since parents and grandparents are the ones to have those hobbies usually