さえ vs でも in term of extreme example
Pls feel free to provide example
According to the Kojien 6th edition (Japanese dictionary), here are the examples.
「でも」 means "pick something as an extreme example and imply that it is more natural if not the case."
-「子どもでもできる」（＝大人なら当然できる） Even a kid can do that. (Of course, an adult can do it.)
-「初心者でもできる」（＝上級者なら当然できる） Even a beginner can do that. (of course, an expert can.)
-「一枚でもいい」（＝二枚以上なら当然もっといい） Even one is okay. (Two or more is better of course)
-「病をおしてでも行く」（＝元気なら当然行く） I will go even if I am sick. (Of course, I'll go if I'm not.)
-「冗談にでも口にするな」（＝本気なら当然口にするな） Do not say that even if as a joke. (Of course, you should not say it seriously.)
「さえ」 has several meanings including the exact same meaning of 「でも」. So we can also say,
However, we don't say the following. 「一枚でさえいい」 「病をおしてさえ行く」 「冗談にさえ口にするな」
I thought about why we don't but could not figure out. I feel like 「さえ」 is only applicable when the thing you picked is clearly a light, or say, inferior to what you imply. In this case, 子ども ＜ 大人 and 初心者＜上級者 is clear, but 一枚＜二枚以上 depends on the situation and less clear...