PSPACE-completeness of Bloxorz and of games with 2-buttons

Tom C. Van Der Zanden*, Hans L. Bodlaender

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review


    Bloxorz is an online puzzle game where players move a 1 × 1 × 2 block by tilting it on a subset of the two dimensional grid, that also features switches that open and close trapdoors. The puzzle is to move the block from its initial position to an upright position on the goal square. We show that the problem of deciding whether a given Bloxorz level is solvable is PSPACE-complete and that this remains so even when all trapdoors are initially closed or all trapdoors are initially open. We also answer an open question of Viglietta [6], showing that 2- buttons are sufficient for PSPACE-hardness of general puzzle games. We also examine the hardness of some variants of Bloxorz, including variants where the block is a 1 × 1 × 1 cube, and variants with single-use tiles.

    Original languageEnglish
    Title of host publicationAlgorithms and Complexity
    Subtitle of host publication9th International Conference, CIAC 2015, Paris, France, May 20-22, 2015. Proceedings
    EditorsVangelis Th. Paschos , Peter Widmayer
    Number of pages13
    ISBN (Electronic)978-3-319-18173-8
    ISBN (Print)9783319181721
    Publication statusPublished - 2015
    Event9th International Conference on Algorithms and Complexity, CIAC 2015 - Paris, France
    Duration: 20 May 201522 May 2015

    Publication series

    NameLecture Notes in Computer Science
    ISSN (Print)0302-9743
    ISSN (Electronic)1611-3349


    Conference9th International Conference on Algorithms and Complexity, CIAC 2015


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