Redundant is Not Redundant: Automating Efficient Categorical Palette Design Unifying Color & Shape Encodings with CatPAW
Pith reviewed 2026-05-16 06:34 UTC · model grok-4.3
The pith
Redundant color and shape encodings improve accuracy when judging class correlations in scatterplots, with largest gains for five to eight categories.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Four crowdsourced experiments demonstrate that redundant color-shape encodings enhance accuracy in assessing class-level correlations in scatterplots, with the strongest benefits for five to eight categories and clear interaction effects between specific colors and shapes. These empirical patterns directly inform the construction of CatPAW, a design tool that produces categorical palettes by unifying color and shape encodings according to the identified high-performing configurations.
What carries the argument
CatPAW, the automated palette design tool that selects and combines colors and shapes into redundant encodings based on the experimental performance data.
If this is right
- Redundancy produces the largest accuracy gains when scatterplots contain five to eight categories.
- Interaction effects require deliberate pairing of colors with shapes rather than arbitrary combinations.
- The CatPAW tool lets designers generate effective palettes without relying on untested assumptions about redundancy.
- Systematic measurement of combined-channel performance advances knowledge of categorical perception in visualizations.
Where Pith is reading between the lines
- The identified pairings could be tested in other chart types such as maps or parallel coordinates where category distinction matters.
- Future experiments with domain experts and real datasets over extended sessions would clarify whether the short-task benefits persist.
- Embedding CatPAW defaults into visualization libraries could shift practice toward empirically supported redundant encodings.
- Extending the approach to additional visual channels like size or texture might reveal broader rules for multi-channel redundancy.
Load-bearing premise
Performance measured in short crowdsourced tasks on synthetic scatterplots will generalize to expert analysts working with real data and longer viewing times.
What would settle it
A controlled study in which professional analysts judge class correlations on authentic datasets using the tool's recommended redundant palettes versus standard non-redundant ones, checking whether accuracy improvements for five-to-eight categories disappear.
Figures
read the original abstract
Colors and shapes are commonly used to encode categories in multi-class scatterplots. Designers often combine the two channels to create redundant encodings, aiming to enhance class distinctions. However, evidence for the effectiveness of redundancy remains conflicted, and guidelines for constructing effective combinations are limited. This paper presents four crowdsourced experiments evaluating redundant color-shape encodings and identifying high-performing configurations across different category numbers. Results show that redundancy significantly improves accuracy in assessing class-level correlations, with the strongest benefits for 5-8 categories. We also find pronounced interaction effects between colors and shapes, underscoring the need for careful pairing in designing redundant encodings. Drawing on these findings, we introduce a categorical palette design tool that enables designers to construct empirically grounded palettes for effective categorical visualization. Our work advances understanding of categorical perception in data visualization by systematically identifying effective redundant color-shape combinations and embedding these insights into a practical palette design tool.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper claims that redundant color-shape encodings improve accuracy in assessing class-level correlations in multi-class scatterplots (strongest for 5-8 categories), identifies interaction effects between the channels, and introduces the CatPAW tool to automate empirically grounded categorical palette design. These conclusions rest on four crowdsourced experiments using synthetic scatterplots.
Significance. If the results hold, the work would supply concrete empirical guidance for combining color and shape in categorical visualizations and deliver a usable design tool, advancing perceptual understanding in visualization and HCI.
major comments (2)
- [Experiments 1-4] The four experiments are presented without participant counts, exclusion criteria, statistical tests, or error bars, so the reported accuracy gains and the claim that redundancy 'significantly improves' performance cannot be verified.
- [Discussion and Implications] The practical recommendations for palette design (including CatPAW) rest on the untested assumption that short crowdsourced tasks on synthetic data generalize to expert analysts, real datasets, and longer viewing times; no transfer evidence is supplied.
minor comments (1)
- [Results figures] Figure captions and axis labels in the result plots should explicitly state the number of categories and the exact correlation-assessment metric used.
Simulated Author's Rebuttal
We thank the referee for the constructive feedback. We will revise the manuscript to address the reporting of experimental details and to strengthen the discussion of limitations and implications.
read point-by-point responses
-
Referee: [Experiments 1-4] The four experiments are presented without participant counts, exclusion criteria, statistical tests, or error bars, so the reported accuracy gains and the claim that redundancy 'significantly improves' performance cannot be verified.
Authors: We agree that these details are necessary for full verification. We will revise the methods and results sections to report the exact participant counts per experiment, the exclusion criteria (including attention checks and performance thresholds), the complete statistical tests performed (including test statistics, degrees of freedom, p-values, and effect sizes), and ensure all figures include clearly labeled error bars. These elements were collected during the studies but were inadvertently omitted from the initial submission due to length constraints. revision: yes
-
Referee: [Discussion and Implications] The practical recommendations for palette design (including CatPAW) rest on the untested assumption that short crowdsourced tasks on synthetic data generalize to expert analysts, real datasets, and longer viewing times; no transfer evidence is supplied.
Authors: We acknowledge this limitation. Our experiments were designed as controlled perceptual studies to isolate channel interactions, and we do not provide direct evidence of transfer to expert users, real-world data, or extended sessions. In the revision we will expand the discussion to explicitly note these boundaries, qualify the recommendations accordingly, and suggest targeted follow-up studies. The CatPAW tool remains grounded in the observed perceptual patterns from the controlled tasks, which we believe still offers immediate practical utility while highlighting the need for further validation. revision: partial
Circularity Check
No circularity: purely empirical study with no derivations or self-referential fits
full rationale
The paper reports four crowdsourced experiments measuring accuracy on synthetic scatterplots for redundant color-shape encodings. All central claims (redundancy improves accuracy, strongest for 5-8 categories, interaction effects) are direct statistical outcomes from participant data. No equations, fitted parameters renamed as predictions, self-citation load-bearing premises, or ansatzes appear in the derivation chain. The CatPAW tool is constructed from these experimental results rather than any closed loop. The study is self-contained against its own benchmarks and contains no load-bearing steps that reduce to inputs by construction.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption Standard assumptions of crowdsourced perceptual experiments (e.g., participant attention, task comprehension)
Lean theorems connected to this paper
-
IndisputableMonolith/Foundation/AbsoluteFloorClosure.leanreality_from_one_distinction unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
Results show that redundancy significantly improves accuracy in assessing class-level correlations, with the strongest benefits for 5-8 categories.
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
Sven Bachthaler and Daniel Weiskopf. 2008. Continuous scatterplots.IEEE transactions on visualization and computer graphics14, 6 (2008), 1428–1435
work page 2008
-
[2]
Emily Badger. 2018. What’s the right number of taxis (or Uber or Lyft cars) in a city.New York Times(2018)
work page 2018
-
[3]
Caroline Barras and Dirk Kerzel. 2017. Target-nontarget similarity decreases search efficiency and increases stimulus-driven control in visual search.Attention, Perception, & Psychophysics79, 7 (2017), 2037–2043
work page 2017
-
[4]
Beth A Barstow, Jason Vice, Sean Bowman, Tapan Mehta, Seanna Kringen, Peter Axelson, and Sangeetha Padalabalanarayanan. 2019. Examining perceptions of existing and newly created accessibility symbols.Disability and Health Journal 12, 2 (2019), 180–186
work page 2019
-
[5]
Lyn Bartram, Abhisekh Patra, and Maureen Stone. 2017. Affective color in visual- ization. InProceedings of the 2017 CHI conference on human factors in computing systems. 1364–1374
work page 2017
-
[6]
1991.Basic color terms: Their universality and evolution
Brent Berlin and Paul Kay. 1991.Basic color terms: Their universality and evolution. Univ of California Press
work page 1991
-
[7]
Rita Borgo, Luana Micallef, Benjamin Bach, F McGee, and B Lee. 2018. Information Visualization Evaluation Using Crowdsourcing.Comput. Graph. Forum37, 3 (2018), 573–595. doi:10.1111/cgf.13444
-
[8]
Michelle A Borkin, Azalea A Vo, Zoya Bylinskii, Phillip Isola, Shashank Sunkavalli, Aude Oliva, and Hanspeter Pfister. 2013. What makes a visualization memorable? IEEE Trans. Vis. Comput. Graph.19, 12 (2013), 2306–2315
work page 2013
-
[9]
David Borland and Russell M Taylor Ii. 2007. Rainbow color map (still) considered harmful.IEEE Comput. Graph. Appl.27, 2 (2007), 14–17
work page 2007
-
[10]
Michael Bostock, Vadim Ogievetsky, and Jeffrey Heer. 2011. D3Data-Driven Documents.IEEE Trans. Vis. Comput. Graph.17, 12 (2011), 2301–2309
work page 2011
-
[11]
Timothy F Brady and Joshua B Tenenbaum. 2013. A probabilistic model of visual working memory: Incorporating higher order regularities into working memory capacity estimates.Psychological review120, 1 (2013), 85
work page 2013
-
[12]
David Burlinson, Kalpathi Subramanian, and Paula Goolkasian. 2017. Open vs. closed shapes: New perceptual categories?IEEE Trans. Vis. Comput. Graph.24, 1 (2017), 574–583. doi:10.1109/TVCG.2017.2745086
-
[13]
Carto. 2022. Location Intelligence & GIS for cloud natives. https://carto.com/
work page 2022
-
[14]
Sarun Charumilind, Matt Craven, Jessica Lamb, Adam Sabow, Shubham Singhal, and Matt Wilson. 2022. When will the COVID-19 pandemic end?McKinsey & Company: https://www.mckinsey.com/industries/healthcare/our-insights/when-will- the-covid-19-pandemic-end(2022)
work page 2022
-
[15]
Haidong Chen, Wei Chen, Honghui Mei, Zhiqi Liu, Kun Zhou, Weifeng Chen, Wentao Gu, and Kwan-Liu Ma. 2014. Visual abstraction and exploration of multi- class scatterplots.IEEE Transactions on Visualization and Computer Graphics20, 12 (2014), 1683–1692
work page 2014
-
[16]
William Cleveland and Robert McGill. 1984. Graphical perception: Theory, experimentation, and application to the development of graphical methods.J. Amer. Statist. Assoc.79, 387 (1984), 531–554
work page 1984
-
[17]
Michael Correll and Jeffrey Heer. 2017. Regression by eye: Estimating trends in bivariate visualizations. InProc. ACM Hum. Factors Comput. Syst. (CHI). 1387–
work page 2017
-
[18]
doi:10.1145/3025453.3025922
-
[19]
Çağatay Demiralp, Michael S Bernstein, and Jeffrey Heer. 2014. Learning per- ceptual kernels for visualization design.IEEE Trans. Vis. Comput. Graph.20, 12 (2014), 1933–1942. doi:10.1109/TVCG.2014.2346978
-
[20]
Madison A Elliott, Christine Nothelfer, Cindy Xiong, and Danielle Albers Szafir
-
[21]
A Design Space of Vision Science Methods for Visualization Research.IEEE Trans. Vis. Comput. Graph.(2020). doi:10.1109/TVCG.2020.3029413
-
[22]
Geoffrey Ellis and Alan Dix. 2007. A taxonomy of clutter reduction for information visualisation.IEEE Trans. Vis. Comput. Graph.13, 6 (2007), 1216–1223
work page 2007
-
[23]
Steven L Franconeri, Lace M Padilla, Priti Shah, Jeffrey M Zacks, and Jessica Hull- man. 2021. The science of visual data communication: What works.Psychological Science in the Public Interest22, 3 (2021), 110–161
work page 2021
-
[24]
Michael Gleicher, Danielle Albers, Rick Walker, Ilir Jusufi, Charles D Hansen, and Jonathan C Roberts. 2011. Visual comparison for information visualization. Information Visualization10, 4 (2011), 289–309
work page 2011
-
[25]
Michael Gleicher, Michael Correll, Christine Nothelfer, and Steven Franconeri
-
[26]
Perception of average value in multiclass scatterplots.IEEE Trans. Vis. Comput. Graph.19 (2013). doi:10.1109/TVCG.2013.183
-
[27]
Robert L Goldstone and Andrew T Hendrickson. 2010. Categorical perception. Wiley Interdiscip. Rev.: Cogn. Sci.1, 1 (2010), 69–78. doi:10.1002/wcs.26
-
[28]
Connor Gramazio. 2019. d3-jnd: Perceptual color difference tool for D3.js. https: //github.com/connorgr/d3-jnd. GitHub repository. Accessed: 2025-03-30
work page 2019
-
[29]
Connor C Gramazio, David H Laidlaw, and Karen B Schloss. 2016. Colorgorical: Creating discriminable and preferable color palettes for information visualization. IEEE Trans. Vis. Comput. Graph.23, 1 (2016), 521–530. doi:10.1109/TVCG.2016. 2598918
-
[30]
Maxene Graze and Jonathan Schwabish. 2024. Building color palettes in your data visualization style guides.Journal of the American Medical Informatics Association 31, 2 (2024), 488–498
work page 2024
-
[31]
Paul Green-Armytage. 2010. A colour alphabet and the limits of colour coding. JAIC-Journal of the International Colour Association5 (2010)
work page 2010
-
[32]
Tejas Guha, Elana J Fertig, and Atul Deshpande. 2022. Generating colorblind- friendly scatter plots for single-cell data.Elife11 (2022), e82128
work page 2022
-
[33]
Charles R. Harris, K. Jarrod Millman, Stéfan J van der Walt, Ralf Gommers, Pauli Virtanen, David Cournapeau, Eric Wieser, Julian Taylor, Sebastian Berg, Nathaniel J. Smith, Robert Kern, Matti Picus, Stephan Hoyer, Marten H. van Kerkwijk, Matthew Brett, Allan Haldane, Jaime Fernández del Río, Mark Wiebe, Pearu Peterson, Pierre Gérard-Marchant, Kevin Sheppa...
-
[34]
Lane Harrison, Fumeng Yang, Steven Franconeri, and Remco Chang. 2014. Rank- ing visualizations of correlation using weber’s law.IEEE transactions on visual- ization and computer graphics20, 12 (2014), 1943–1952. doi:10.1109/TVCG.2014. 2346979
-
[35]
Mark Harrower and Cynthia A Brewer. 2003. ColorBrewer. org: an online tool for selecting colour schemes for maps.Cartogr. J.40, 1 (2003), 27–37. doi:10.1179/ 000870403235002042
work page 2003
-
[36]
Jeffrey Heer and Michael Bostock. 2010. Crowdsourcing graphical perception: using mechanical turk to assess visualization design. InProc. ACM Hum. Factors Comput. Syst. (CHI). doi:10.1145/1753326.1753357
-
[37]
Jeffrey Heer and Maureen Stone. 2012. Color naming models for color selection, image editing and palette design. InProc. ACM Hum. Factors Comput. Syst. (CHI). 1007–1016. doi:10.1145/2207676.2208547
-
[38]
Katherine L Hermann, Shridhar R Singh, Isabelle A Rosenthal, Dimitrios Pantazis, and Bevil R Conway. 2022. Temporal dynamics of the neural representation of hue and luminance polarity.Nature communications13, 1 (2022), 661
work page 2022
-
[39]
Matt-Heun Hong, Zachary Nolan Sunberg, and Danielle Albers Szafir. 2024. Cieran: Designing Sequential Colormaps via In-Situ Active Preference Learning. InProceedings of the 2024 CHI Conference on Human Factors in Computing Systems. 1–15
work page 2024
-
[40]
Matt-Heun Hong, Jessica K Witt, and Danielle Albers Szafir. 2021. The Weighted Average Illusion: Biases in Perceived Mean Position in Scatterplots.IEEE Trans. Vis. Comput. Graph.28, 1 (2021), 987–997. doi:10.1109/tvcg.2021.3114783
-
[41]
Liqiang Huang. 2020. Space of preattentive shape features.Journal of vision20, 4 (2020), 10–10
work page 2020
-
[42]
2022.MATLAB version: 9.13.0 (R2022b)
The MathWorks Inc. 2022.MATLAB version: 9.13.0 (R2022b). Natick, Mas- sachusetts, United States. https://www.mathworks.com
work page 2022
-
[43]
2024.ISO 9186-2:2008 - Graphical symbols — Test methods
International Organization for Standardization. 2024.ISO 9186-2:2008 - Graphical symbols — Test methods. https://www.iso.org/standard/43484.html
work page 2024
-
[44]
Matthew Kay and Jeffrey Heer. 2015. Beyond weber’s law: A second look at ranking visualizations of correlation.IEEE Trans. Vis. Comput. Graph.22, 1 (2015), 469–478. doi:10.1109/TVCG.2015.2467671
-
[45]
Max Kinateder, William H Warren, and Karen B Schloss. 2019. What color are emergency exit signs? Egress behavior differs from verbal report.Appl. Ergon.75 (2019), 155–160
work page 2019
-
[46]
Robert Kosara. 2016. An empire built on sand: Reexamining what we think we know about visualization. InBELIV
work page 2016
-
[47]
Sharon Lin, Julie Fortuna, Chinmay Kulkarni, Maureen Stone, and Jeffrey Heer
-
[48]
Selecting Semantically-Resonant Colors for Data Visualization.Comput. Graph. Forum32, 3pt4 (2013), 401–410. doi:10.1111/cgf.12127
-
[49]
Sheng Long and Matthew Kay. 2024. To cut or not to cut? a systematic exploration of y-axis truncation. InProceedings of the 2024 CHI Conference on Human Factors in Computing Systems. 1–12
work page 2024
- [50]
-
[51]
Geoffroy Martin. 2015. iWantHue: Colors for Data Scientists. https://medialab. github.io/iwanthue/. Accessed: 2025-03-26
work page 2015
-
[52]
Adrian Mayorga and Michael Gleicher. 2013. Splatterplots: Overcoming overdraw in scatter plots.IEEE Trans. Vis. Comput. Graph.19, 9 (2013), 1526–1538
work page 2013
-
[53]
Microsoft Corporation. 2024.Microsoft Excel. https://office.microsoft.com/excel
work page 2024
-
[54]
2014.Visualization analysis and design
Tamara Munzner. 2014.Visualization analysis and design. CRC press
work page 2014
-
[55]
Christine Nothelfer, Michael Gleicher, and Steven Franconeri. 2017. Redundant encoding strengthens segmentation and grouping in visual displays of data. Journal of Experimental Psychology: Human Perception and Performance43, 9 (2017), 1667
work page 2017
-
[56]
Ghulam Jilani Quadri and Paul Rosen. 2021. A survey of perception-based visualization studies by task.IEEE Trans. Vis. Comput. Graph.28, 12 (2021). doi:10.1109/tvcg.2021.3098240
-
[57]
Ghulam Jilani Quadri, Arran Zeyu Wang, Zhehao Wang, Jennifer Adorno, Paul Rosen, and Danielle Albers Szafir. 2024. Do You See What I See? A Qualitative Study Eliciting High-Level Visualization Comprehension. InACM CHI. 1–26. doi:10.1145/3613904.3642813
-
[58]
2021.R: A Language and Environment for Statistical Computing
R Core Team. 2021.R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project. CHI ’26, April 13–17, 2026, Barcelona, Spain Chin Tseng, Arran Zeyu Wang, Ghulam Jilani Quadri, and Danielle Albers Szafir org/
work page 2021
-
[59]
Ronald Rensink and Gideon Baldridge. 2010. The perception of correlation in scatterplots.Comput. Graph. Forum29, 3 (2010), 1203–1210. doi:10.1111/j.1467- 8659.2009.01694.x
-
[60]
Ronald A Rensink. 2013. On the prospects for a science of visualization. In Handbook of human centric visualization. Springer, 147–175
work page 2013
-
[61]
Hannah Ritchie and Max Roser. 2019. Age structure.Our World in Data(2019)
work page 2019
-
[62]
Francesca Samsel, Lyn Bartram, and Annie Bares. 2018. Art, affect and color: Cre- ating engaging expressive scientific visualization. In2018 IEEE VIS Arts Program (VISAP). IEEE, 1–9
work page 2018
-
[64]
Abhraneel Sarma, Shunan Guo, Jane Hoffswell, Ryan Rossi, Fan Du, Eunyee Koh, and Matthew Kay. 2022. Evaluating the Use of Uncertainty Visualisations for Imputations of Data Missing At Random in Scatterplots.IEEE Trans. Vis. Comput. Graph.29, 1 (2022), 602–612
work page 2022
-
[65]
Karen B Schloss, Connor C Gramazio, Allison T Silverman, Madeline L Parker, and Audrey S Wang. 2018. Mapping color to meaning in colormap data visualizations. IEEE Trans. Vis. Comput. Graph.25, 1 (2018), 810–819. doi:10.1109/TVCG.2018. 2865147
-
[66]
Karen B Schloss, Laurent Lessard, Charlotte S Walmsley, and Kathleen Foley. 2018. Color inference in visual communication: the meaning of colors in recycling. Cogn. Res.: Princ. Implic.3, 1 (2018), 1–17
work page 2018
-
[67]
Karen B Schloss and Stephen E Palmer. 2010. Aesthetics of color combinations. InHuman Vision and Electronic Imaging XV, Vol. 7527. SPIE, 365–376
work page 2010
-
[68]
Karen B Schloss, Eli D Strauss, and Stephen E Palmer. 2013. Object color prefer- ences.Color Research & Application38, 6 (2013), 393–411
work page 2013
-
[69]
Karen B Schloss, Christoph Witzel, and Leslie Y Lai. 2020. Blue hues don’t bring the blues: questioning conventional notions of color–emotion associations. Journal of the Optical Society of America A37, 5 (2020), 813–824
work page 2020
-
[70]
Michael Sedlmair, Andrada Tatu, Tamara Munzner, and Melanie Tory. 2012. A taxonomy of visual cluster separation factors.Comput. Graph. Forum31, 3pt4 (2012), 1335–1344
work page 2012
-
[71]
Gaurav Sharma, Wencheng Wu, and Edul N Dalal. 2005. The CIEDE2000 color- difference formula: Implementation notes, supplementary test data, and mathe- matical observations.Color Res. Appl.30, 1 (2005), 21–30
work page 2005
-
[72]
Stephen Smart and Danielle Albers Szafir. 2019. Measuring the Separability of Shape, Size, and Color in Scatterplots. InProc. ACM Hum. Factors Comput. Syst. (CHI). 669. doi:10.1145/3290605.3300899
-
[73]
Stephen Smart, Keke Wu, and Danielle Albers Szafir. 2019. Color crafting: Au- tomating the construction of designer quality color ramps.IEEE Trans. Vis. Comput. Graph.26, 1 (2019), 1215–1225
work page 2019
-
[74]
Inc. Statgraphics Technologies. 2022. Statgraphics19. https://www.statgraphics. com/
work page 2022
-
[75]
Maureen Stone. 2006. Choosing colors for data visualization.Business Intelligence Network2 (2006)
work page 2006
-
[76]
Maureen Stone, Danielle Albers Szafir, and Vidya Setlur. 2014. An engineering model for color difference as a function of size. InColor and Imaging Conference, Vol. 2014. 253–258
work page 2014
-
[77]
Danielle Albers Szafir. 2018. Modeling color difference for visualization design. IEEE Trans. Vis. Comput. Graph.24, 1 (2018), 392–401. doi:10.1109/TVCG.2017. 2744359
-
[78]
Danielle Albers Szafir, Rita Borgo, Min Chen, Darren J Edwards, Brian Fisher, and Lace Padilla. 2023.Visualization Psychology. Springer Nature
work page 2023
-
[79]
Danielle Albers Szafir, Steve Haroz, Michael Gleicher, and Steven Franconeri
-
[80]
Four types of ensemble coding in data visualizations.Journal of Vision16, 5 (2016), 11–11. doi:10.1167/16.5.11
-
[81]
Danielle Albers Szafir, Maureen Stone, and Michael Gleicher. 2014. Adapting color difference for design. InColor and Imaging Conference, Vol. 22. Society for Imaging Science and Technology, 228–233
work page 2014
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.