Cafe wall illusion

All the lines are actually parallel.

I see increasing and decreasing slopes, black and white blocks. See Wikipedia.

Gray bars illusion

I see rectangular gray boxes.

Ouchi

Move your frame of reference to see the effect.

It looks like a black and white frame, with reversing patterns.

Fraser illusion

All the lines are actually parallel.

I see increasing and decreasing slopes, with diagonal patterns.

Fraser-Wilcox illusion

I see three moving columns.

Parallel curves

These curves are the same offset apart for every x, even though it looks like they converge.

I see two lines that appear to be converging at the top.

Snake oculogyral illusion

I see rotating circles.

References

Based on the illusions knitrBootstrap vignette which itself is based on Kohske Takahashi’s code at http://rpubs.com/kohske/R-de-illusion.

Reproducibility

## Session info --------------------------------------------------------------
##  setting  value                       
##  version  R version 3.2.0 (2015-04-16)
##  system   x86_64, darwin13.4.0        
##  ui       X11                         
##  language (EN)                        
##  collate  en_US.UTF-8                 
##  tz       America/New_York
## Packages ------------------------------------------------------------------
##  package   * version date       source        
##  curl        0.8     2015-06-06 CRAN (R 3.2.0)
##  devtools  * 1.8.0   2015-05-09 CRAN (R 3.2.0)
##  digest      0.6.8   2014-12-31 CRAN (R 3.2.0)
##  evaluate    0.7     2015-04-21 CRAN (R 3.2.0)
##  formatR     1.2     2015-04-21 CRAN (R 3.2.0)
##  git2r       0.10.1  2015-05-07 CRAN (R 3.2.0)
##  htmltools   0.2.6   2014-09-08 CRAN (R 3.2.0)
##  knitr       1.10.5  2015-05-06 CRAN (R 3.2.0)
##  magrittr    1.5     2014-11-22 CRAN (R 3.2.0)
##  memoise     0.2.1   2014-04-22 CRAN (R 3.2.0)
##  plyr      * 1.8.3   2015-06-12 CRAN (R 3.2.0)
##  Rcpp        0.11.6  2015-05-01 CRAN (R 3.2.0)
##  rmarkdown   0.7     2015-06-13 CRAN (R 3.2.0)
##  rversions   1.0.1   2015-06-06 CRAN (R 3.2.0)
##  stringi     0.4-1   2014-12-14 CRAN (R 3.2.0)
##  stringr     1.0.0   2015-04-30 CRAN (R 3.2.0)
##  xml2        0.1.1   2015-06-02 CRAN (R 3.2.0)
##  yaml        2.1.13  2014-06-12 CRAN (R 3.2.0)

Date this report was generated: 2015-06-19 10:35:11.