Error(s) in re-building vignettes:
--- re-building ‘gallery.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 32-36 (gallery.Rmd) 
Error: processing vignette 'gallery.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘gallery.Rmd’

--- re-building ‘introduction.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 103-110 (introduction.Rmd) 
Error: processing vignette 'introduction.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘introduction.Rmd’

--- re-building ‘under-the-hood.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Warning in grid.Call(C_textBounds, as.graphicsAnnot(x$label), x$x, x$y,  :
  no font could be found for family "Arial"
Quitting from lines 159-201 (under-the-hood.Rmd) 
Error: processing vignette 'under-the-hood.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘under-the-hood.Rmd’

--- re-building ‘venn-diagrams.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 51-58 (venn-diagrams.Rmd) 
Error: processing vignette 'venn-diagrams.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘venn-diagrams.Rmd’

--- re-building ‘visualization.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 85-91 (visualization.Rmd) 
Error: processing vignette 'visualization.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘visualization.Rmd’

SUMMARY: processing the following files failed:
  ‘gallery.Rmd’ ‘introduction.Rmd’ ‘under-the-hood.Rmd’
  ‘venn-diagrams.Rmd’ ‘visualization.Rmd’

Error: Vignette re-building failed.
Execution halted