On some buildings in Moscow (and other cities in European part of Russia) there are carvings of three interconnected wreaths.
For example, some are on the Pushkin Museum building on Prechistenka:



This building was erected around 1814, but unfortunately I didn't find information about the meaning of the carvings (apart from the shield with emblem of the building original owners). As usual, people are blaming Masons and I wouldn't be surprised if it is a part of masonic symbolism, however, I didn't find anything exactly like that. I.e., IOOF symbol is similar, but it should be chain which would look different. It is also not Borromean Rings which should be interlocked.
So, where does this symbol come from?
A couple more images from other sites: