These are Slitherlink puzzles. I generated these using pzprRT by semiexp, a wonderful real-time solver, based on remembering similar puzzles with a subgrid of 3s (and their explanation, which was in Japanese and so I could only read through machine translation), and then wen on Puzzlers Club was able to find a nice logical solve path for them, so I decided that I liked them enough to post them here.

The solution is something I might post later, but not on this exact post right now, because it’s a very neat one (if possibly quicker to bifurcate than to properly solve) though the title gives a very big hint.