The topmost sheet is the current 'object', and next sheet underneath it is the 'prototoype' of the current object, usually referred to via the "__proto__" key.
You can occlude values of the same key, like you can occlude pictures drawn on the same spot.
You can only write to the topmost object, as in a stack of glass, where you can only draw on top (unless you manually uncover the sheets).
This analogy isn't perfect. In real life, you need to choose which sheet to put upon a stack -- that is, two sheets can't simultaneously be the topmost sheet. But in Javascript there is superposition, so to speak.
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I have found that you can have a Pythonic class system by mixing CoffeeScript semantic sugar, and the Object.setProperty system. You can have Rubyesq class (module) property injection as well.
https://github.com/jaekwon/Cardamom/blob/master/src/clazz.coffee