This question already has an answer here:

I was wondering if there is any package or a simple snippet I could use to get the kind of corners shown in the picture for theorems and definitions.

Thanks in advance.

Source: MIT Mathematics of Machine Learning course.

marked as duplicate by CarLaTeX, Raaja, siracusa, Stefan Pinnow, schtandard Jun 22 at 8:00

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • Yes, such packages exist and they are called tcolorbox and tcolorbox. Just do a google image search for site:tex.stackexchange.com tcolorbox theorem and click on whatever looks promising. This will give you an idea and also a starting point for a question which is more appreciated. – user121799 Jun 22 at 1:38
  • @marmot I found some packages like that one but they provide full boxes. I didn't see any example showing isolated corners. Maybe it's possible to do it with the tcolorbox tools, but I have no idea how. – Alan Rapoport Jun 22 at 1:43

This is to give you a start. All I did was to look up an answer, I randomly chose this one and cooked it down to


\newtcbtheorem[number within=chapter]{Theorem}{}{
        enhanced,sharp corners,colback=white,colframe=white,top=-0.5em,
        \draw[gray!40,line width=3pt] ([yshift=-1cm]frame.north west) 
        |- ++ (1,1) ([yshift=1cm]frame.south east) |- ++ (-1,-1);


    No three positive integers \(a\), \(b\) and \(c\) satisfy the equation \(a^{n} + b^{n} = c^{n}\) for any integer greater than two.

enter image description here

The fact that the answer I link to achieves so much more than this one may give you an idea of what it possible. Note that the answer I link to answers a question in which the user provided an MWE, such questions tend to get received better.

  • Thanks a lot. That would definitely work. I didn't provide any MWE because I had no idea that an example like the one in the link you passed me could be adapted to my needs. This is the first time I heard of tcolorbox. – Alan Rapoport Jun 22 at 15:20

Not the answer you're looking for? Browse other questions tagged or ask your own question.