#A20: RB Loop

 While a background in Yajilin does help for some of the harder puzzles, it's not really the main focus of the genre, as maybe a third of the puzzles I've seen in this genre don't use numeric clues at all. It's a simple concept at its core but it does make for some good puzzles.

https://pedros.works/paper-puzzle-player.html?W=7x7&L=v2(2)u13(1)l4(0)r10(2)l4v5&G=rb-loop

This one might be nonunique:

https://pedros.works/paper-puzzle-player.html?W=12x20&L=v0c21c1c1c1c1x2x2x2(2)u1(1)r1c8c2c2x1(0)d6(2)u1c8cx2p2c1c2v4c10c2p4p1v1p1v2c1(2)r8(1)d1p6p2v2(2)l3(1)l1(0)u5(2)l1c3p3p2(0)u5(2)r1v8c1p4v4v1v1v1v1cx9v4v2v3v2(2)d8(1)u1x6v3v2(0)l8(2)d1x1x2x2v2v1v2c22&G=rb-loop