One of the non-standard puzzle types in the Serbian Grand Prix round is Shikaku with clues that are off by one (as “Shikaku Liars”). Here’s a practice puzzle.
Rules Split the grid into rectangles composed of grid cells, containing one clue each, such that the size of each rectangle is equal to the corresponding clue ±1. Or see the instruction booklet.
There’s another easier puzzle of this type on the Rätselportal: Knapp daneben – Rechtecke. Then, in the knapp daneben instance of the Hausigel Contest Series. The double-clue Shikakus on croco should also be good practice: 2014-03-01, 2014-04-04.