Tetromino Slitherlink

Rules: In addition to regular Slitherlink rules, some clues are hidden. Each tetromino covers four different clues: a zero, a one, a two, and a three.




This variant was invented by Ivan Koswara (the original rules have the boundaries between tetrominoes hidden as well). Here is the first puzzle of the type, and here is a further Tetromino Liar variation.