Meaning of こった in Xと、こったのもあった

Question

From the story 愛の鍵 by 星新ー:

ある人のは「チューリップが咲いた。」と言えば開いたし「しっかりしなくちゃあ。」と言うのもあった。なかには「王さまの耳はロバの耳。」などと、こったのもあった。
One person's phrase to open the lock was to say "The tulips have bloomed". There was also one which said "You must make it secure". Among them, there was, for example, "The ears of a king are the ears of a robber".

The story seems to be describing locks shaped like ears that people unlock by whispering phrases into them.

I cannot understand the meaning of こった in the second sentence. Maybe 請う would fit with the quotative particle, but the dictionary says that this means 'ask' which doesn't really seem to fit the context.

More generally I'm having trouble with the the two の particles marked in bold. In と言うのもあった is の a pronoun describing a person or a phrase, i.e. is it 'there was one person who said ' or 'there was one phrase which said'? My guess is that it matches with the の in ある人のは, so it is one person with two phrases. Likewise I'm struggling with the の in こったの.

Answer 1

This こる is 凝る, which loosely means "to elaborate", "to have a variety of ideas", etc. See also 趣向を凝らす.

ある人のは「チューリップが咲いた。」と言えば開いたし「しっかりしなくちゃあ。」と言うのもあった。なかには「王さまの耳はロバの耳。」などと、こったのもあった。

This sentence has many の's, but they all basically mean "one", or "lock".

• ある人の means "one person's lock" (it's like 私の meaning "mine").
• 「しっかりしなくちゃあ」と言うの = 「しっかりしなくちゃあ」と言うもの = one (a lock) to which one (must) say しっかりしなくちゃあ
• こったの = こったもの = 凝った鍵 = elaborate/tricky lock