TANGIBLE TETRIS mixed-reality world, you can pick up the tangible tetrominoes Meng Wang, B430, Academy of Arts and Design, Tsinghua from the screen and put them down to fill gaps under other University, Beijing, 100084, China. Email: m- virtual blocks. As we expected, these two different actions STATEMENTS [email protected]. create new strategies and forms of interaction in the game play. Haipeng Mi, B430, Academy of Arts and Design, Tsinghua Implementation University, Beijing, 100084, China. Email: The hinged structure of the tangible tetromino is inspired by [email protected]. research on hinged dissections of polyominoes and polyforms See www.mitpressjournals.org/toc/leon/52/2 for supplemental files [1–3]. A tetromino has four blocks, and if the blocks are con- associated with this issue. nected with three hinges at specific corners (Fig. 2, middle), Submitted: 16 August 2017 the tetromino can transform into any of its seven distinct shapes via hinged rotation. Thus, we put motors in each corner Abstract to drive and rotate the hinges, so that the physical tetromino Tangible Tetris is a mixed-reality interactive game allowing play with a physi- can receive digital commands and change its shape on the cal transformable tetromino in a virtual playfield. The extension from game playground. Figure 2 also shows all the shapes of the tetromi- world to the physical brings plenty of new characteristics, strategies and fun to the classic game, as well as more possibilities in interactive art. no, how the blocks are connected, and how the rotation is done. Some of the shapes can be achieved by simple 180° rota- The game Tetris is a popular use of tetrominoes, the four- tion, but the others may have a 90° rotation. element special case of polyominoes. In a classic Tetris game, As for the playfield, we use the Microsoft PixelSense [4] to a random sequence of tetrominoes falls down to the bottom of present the digital content. Additionally, a marker is used for the playfield. The objective of the game is to manipulate these orientation, and a wireless module is used for communication tetrominoes by moving each piece horizontally and/or rotating with the tetromino. it by 90° at a time, with the goal of creating one or multiple horizontal rows of blocks without any gap. When such a row is Discussion created, it disappears, and any block above the disappearing Virtual domains are becoming a real part of everyday life. rows will fall. With rapid expansion of cyberspace, a unique virtual world is I used to be a hardcore Tetris player; it was the only game forming, containing many characteristics that we could never on my phone before I owned a smartphone. One day, while access in the physical world, as in Tetris. In this case, the researching tangible user interfaces, an idea came to me all of a screen acts as a great wall between the virtual and the physical. sudden: Why not make a Tangible Tetris, which we can touch “As new technologies equip surfaces with interfaces capable of and play with in the physical world? reacting to their environments, a whole new range of visual The idea was fascinating but hard to implement. How would and structural effects is beginning to emerge. Such reactive the player interact with a physical tetromino? How to design technologies as touch-sensitive screens have the potential to rules to make the game fantastic? How would the tetromino Fig. 1. Play with a physical transformable tetromino in the respond to the player? Would it be able to move, transform or virtual playfield of the Tangible Tetris game. (© Meng Wang) vanish? I have to admit these questions puzzled me for a long time. But eventually, I came up with a project that could deal with them and make a cool game. Description To be exact, Tangible Tetris (Fig. 1) is a game in what we call the mixed-reality world—not the virtual or the physical but both of them. The game is played on a large horizontal screen, with digital image and sound—and a physical object with which you can interact. In Tangible Tetris, the tetromino is tangible, which means you can drag it, rotate it, pick it up and put it down. The cool- est thing is that the tetromino can transform into any of the classic Tetris shapes. I am proud to say I achieved this with techniques from geometry and robotics, which I discuss below. The game rules of Tangible Tetris are actually similar to a variant of Tetris rather than to the classic one. No tetrominoes drop, but players can put the tangible tetromino onto the “NEXT” zone of the screen, and it will transform into the shape displayed. A player then places it at the bottom of the screen or onto other virtual blocks—which will add virtual blocks in the playfield. They will then get a new shape to transform in the “NEXT” zone. In order to make the game a little more challenging, at every few steps, a random row of blocks/gaps will be added at the bottom of the playfield. There is a significant difference between Tangible Tetris and virtual Tetris. In classic Tetris, no blocks can go through exist- ing ones to fill the gaps under them—which seems so natural in a 2D world. But with Tangible Tetris, which is in a 3D 182 LEONARDO, Vol. 52, No. 2, pp. 182–-183, 2019 doi:10.1162/LEON_a_01693 ©2019 ISAST Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/leon_a_01693 by guest on 24 September 2021 STATEMENTS Fig. 2. Shapes of the tetromino, connections of the blocks and rotations needed for transformation. A line connecting two blocks means there is a hinge, and the gaps between blocks are exaggerated. (© Meng Wang) turn even the most mundane of objects into a technological veloped—for example, square to regular triangle, square to interface, enabling designers to take functionality to new rectangle, polyominoes containing more pieces, and so on. In heights” [5]. The virtual and the physical merge on the surface fact, it has been proven that we can always find a hinged dis- of the screen. section for two shapes with the same area, making them able to Tangible is a word mostly used in “tangible media,” or “tan- transform into each other [8,9]. The possible interactions are gible user interface (TUI).” A TUI is a user interface in which beyond our imagination. a person interacts with digital information through the physical Making virtual things physical is a very difficult but signifi- environment, building a bridge between the virtual and the cant matter. Eventually, the wall between the virtual and the physical by giving physical forms to digital information, thus physical will be completely obsolete, and a new world that we taking advantage of human abilities to grasp and manipulate can’t envision yet will come to us. physical objects and materials [6]. “Whereas many systems used physical objects to control digital objects, only few ex- Acknowledgments amples of ‘tangibles that push back’ were found. Most systems We thank Ying-Qing Xu for his suggestion, and all other mates for their support in brainstorming, testing, producing the movie and so on and James Ronner for supported only one-way communication, either being an ambi- proofreading the English. This work is supported by National Key Research & ent display or a data manipulation tool” [7]. People can access Development Plan of China under Grant No. 2016YFB1001402. virtual domains in the physical world (e.g. painting with a real brush on a screen), but the converse is still limited. References and Notes Tetris only exists in a virtual world. In Tangible Tetris, we 1. Erik D. Demaine et al., “Hinged Dissection of Polyominoes and Polyforms.” merge the virtual and the physical onto the screen, create a Computational Geometry 31 (2005) pp. 237–262. mixed-reality world and play in it. The added dimension of the 2. Timothy G. Abbott et al., “Hinged Dissections Exist,” Discrete & Computa- playfield brings surprising possibilities to the new game. We tional Geometry 41, No. 1, 150–186 (2012). can interact with the tetromino naturally, with our hands rather 3. Greg N. Frederickson, Hinged Dissections: Swinging and Twisting (Cam- bridge Univ. Press, 2002). than keyboard and mouse. The virtual playfield can respond to our physical manipulation, and the physical transformable 4. Samsung SUR40 with Microsoft® PixelSense™: www.samsung.com/us/business/support/owners/product/samsung-sur40 tetromino can also respond to the change in the virtual world. -with-microsoft-pixelsense-sur40 (accessed 20 November 2018). This dynamic and reciprocal relationship creates a complete 5. Bradley Quinn, Design Futures (London: Merrell, 2011). mixed-reality world, with a two-way window—we can access 6. Hiroshi Ishii and Brygg Ullmer, “Tangible Bits: Towards Seamless Interfaces both sides with counterparts of the other. between People, Bits and Atoms,” Proceedings of the ACM SIGCHI Confer- ence on Human Factors in Computing Systems (ACM, 1997). Future Work 7. Orit Shaer and Eva Hornecker, “Tangible User Interfaces: Past, Present, and To be accurate, transformation is something that we can Future Directions,” Foundations and Trends in Human-Computer Interaction easily achieve in the virtual world but is hard to implement (ACM, 2010). physically. I’m glad to say that what we have created is more 8. Demaine et al. [1]. than Tetris. With the technical scheme we used in Tangible 9. Abbott et al. [2]. Tetris, many other complex transformable systems can be de- Statements 183 Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/leon_a_01693 by guest on 24 September 2021.