<command arg="-root"/>
- <video href="http://www.youtube.com/watch?v=MKZQ5Q7QINM"/>
+ <video href="https://www.youtube.com/watch?v=MKZQ5Q7QINM"/>
<hgroup>
<vgroup>
Third Dimension: Geometry, Computer Graphics, and Higher Dimensions",
Scientific American Library, 1990.
-http://en.wikipedia.org/wiki/Hypercube
-http://en.wikipedia.org/wiki/Tesseract
-http://en.wikipedia.org/wiki/Regular_polytope
+https://en.wikipedia.org/wiki/Hypercube
+https://en.wikipedia.org/wiki/Tesseract
+https://en.wikipedia.org/wiki/Regular_polytope
Written by Carsten Steger; 2003.
</_description>