@inproceedings{bridges2012:447,
  author      = {H\"{o}ft, Hartmut F. W.},
  title       = {Images and Illusions from Orthogonal Pairs of Ellipses},
  pages       = {447--448},
  booktitle   = {Proceedings of Bridges 2012: Mathematics, Music, Art, Architecture, Culture},
  year        = {2012},
  editor      = {Bosch, Robert and McKenna, Douglas and Sarhangi, Reza},
  isbn        = {978-1-938664-00-7},
  issn        = {1099-6702},
  publisher   = {Tessellations Publishing},
  address     = {Phoenix, Arizona},

  url         = {http://archive.bridgesmathart.org/2012/bridges2012-447.html}
}