I'm curious whether there are some effective means to search for duplicates of geometric problems.

Are there some past discussions on it?

@YuiToCheng I guess it depends on the problem. I can imagine that in some cases Google Images might help.

One example I was able to think of: searching for square inside square area site:math.stackexchange.com returns several images related to this problem: Area of a square inside a square created by connecting point-opposite midpoint.

Related meta thread: What is the efficient way to search post with pictures/images?

Of course, for many geometric problems this would be of no help. (If the post contains no images, it cannot be found using Google Images.)

@MartinSleziak Thanks!