{
  "title": "Kaleidoscope mirror angles: copies, seams and wallpaper types",
  "description": "One row per mirror arrangement: two mirrors at eight angles, three mirrors in three triangles and four mirrors in a square or rectangle, with 180° divided by each angle, the copies around each corner, any leftover angle, whether a lopsided drawing breaks, and the wallpaper type.",
  "license": "CC BY 4.0",
  "license_url": "https://creativecommons.org/licenses/by/4.0/",
  "creator": "Drawn Mathematics",
  "page": "https://drawnmathematics.com/symmetry/kaleidoscope/",
  "derived_from": [
    "Two mirrors at 30°, 36°, 40°, 45°, 50°, 60°, 72° and 90°, reflected in turn with exact angle arithmetic; eye on the wedge's centre line at the corner",
    "Mirror boxes reflected with exact coordinates; wallpaper symbols and the columns used to choose them from wallpaper-groups.csv on this site"
  ],
  "method": "Compiled by Drawn Mathematics from the data listed",
  "data_credit": [
    "Computed for this page by exact reflection; the odd-part exception for symmetric drawings and the three-mirror triangles as stated in David Brewster, The Kaleidoscope, 3rd ed. (London, 1870), Chapters II and XIII"
  ]
}