// cpt-city: xkcd/xkcd-heatmap (cpt)
//
// Randall Munroe's heatmap scheme as used in XKCD episode
// 1128, Heatmap
//
// author: Randall Munroe
// copyright: Creative Commons Attribution-NonCommercial 2.5 Generic
// year: 2012
// url: https://phillips.shef.ac.uk/pub/cpt-city/xkcd
#declare xkcd_heatmap =
color_map {
  [0.00000 color rgbf <1.0000,1.0000,1.0000,0.0000>]
  [0.25000 color rgbf <1.0000,1.0000,1.0000,0.0000>]
  [0.25000 color rgbf <0.4902,0.9804,0.3373,0.0000>]
  [0.50000 color rgbf <0.4902,0.9804,0.3373,0.0000>]
  [0.50000 color rgbf <0.9961,1.0000,0.3373,0.0000>]
  [0.75000 color rgbf <0.9961,1.0000,0.3373,0.0000>]
  [0.75000 color rgbf <1.0000,0.5333,0.3843,0.0000>]
  [1.00000 color rgbf <1.0000,0.5333,0.3843,0.0000>]
}