Calabi–Yau space space manifold

https://en.wikipedia.org/wiki/Calabi%E2%80%93Yau_manifold

http://www.calabi-portal.net

http://www.dummies.com/how-to/content/string-theory-and-calabiyau-manifolds.html

https://www.google.ca/search?q=calabi-yau+space&espv=2&biw=2133&bih=1078&source=lnms&sa=X&ved=0ahUKEwjfp_DZydnKAhVU7WMKHfnwA8IQ_AUIBigA&dpr=0.9