@article{Andersson_2007, title={HIROIMONO is NP-complete}, volume={14}, url={https://tidsskrift.dk/brics/article/view/21924}, DOI={10.7146/brics.v14i1.21924}, abstractNote={In a Hiroimono puzzle, one must collect a set of stones from a square grid, moving along grid lines, picking up stones as one encounters them, and changing direction only when one picks up a stone. We show that deciding the solvability of such puzzles is NP-complete.}, number={1}, journal={BRICS Report Series}, author={Andersson, Daniel}, year={2007}, month={Jan.} }