Þakkir

Ljósmyndir
École Polytechnique, polytechnique.edu
Université de Montréal, umontreal.ca

Chistopher Jones, fotolia.com
Thinkstock 2012, thinkstockphotos.com

Jay Han, jay-han.com
Nalhcal, deviantart.com

David Ferreira, iconfinder.com
Gakuseisean, iconfinder.com
La Glanz Studio, iconarchive.com