<command arg="-root"/>
+ <video href="https://www.youtube.com/watch?v=MKZQ5Q7QINM"/>
+
<hgroup>
<vgroup>
<select id="display-mode">
<xscreensaver-updater />
<_description>
-
-This shows one of the six regular 4D polytopes rotating in 4D.
+The six regular 4D polytopes rotating in 4D.
Inspired by H.S.M Coxeter's book "Regular Polytopes", 3rd Edition,
Dover Publications, Inc., 1973, and Thomas Banchoff's book "Beyond the
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>