XにXを - Intensifying the meaning of X?

Japanese
#1

I saw this in some sample sentences, and it seems to mean that the meaning of X is intensified, but I want to double check that I understood it right.

  • 努力に努力を重ねて何とか産後の体を引き締めようとしたけれど、育児に追われてそれどころではありませんでした。
    I tried to tighten my postpartum body through continuous effort , but I was too busy with childcare to focus on it.
  • 嘘に嘘を重ねても自分が苦しくなるばかりなのでそろそろ白状した方が良いよ。
    It’s time for you to come clean, because piling lie on lie will only make you suffer.
  • 苦労に苦労を重ねた結果、今までで一番納得のいく絵を描く事が出来ました。
    After a lot of painstaking work, I was able to draw the most satisfying picture I have ever drawn.

I’d search for this in the bunpro library, but I don’t know what the lesson page is called.

#2

It’s more to do with the verb 重ねる meaning to stack or overlay, so the idea is taking something and doing it over and over, or so.

#3

Oh, I totally missed that! I thought it had to do with the particles alone.
Are there rules to the stacking? Like they must be nouns, or can you do that with verbs, too? Can anything be stacked?

Is it possible to say … ?

  • 勉強に勉強を重ねる
  • 頑張るに頑張るを重ねる
  • 事件に事件を重ねる
  • 正直に正直を重ねる
  • 渋滞に渋滞を重ねる
#4

That much I couldn’t tell you. In my head of yours, 勉強 and 事件 sound reasonable but less sure of the others