From http://www.jwz.org/xscreensaver/xscreensaver-5.33.tar.gz

[xscreensaver] / hacks / config / projectiveplane.xml

diff --git a/hacks/config/projectiveplane.xml b/hacks/config/projectiveplane.xml
index ad51832e918c66d0bd63b8597f180c680094c09b..fc625a9ed850ac0997a7d127699b3fe158769b40 100644 (file)
--- a/hacks/config/projectiveplane.xml
+++ b/hacks/config/projectiveplane.xml
@@ -139,10 +139,10 @@ in 4D or walk on it while it rotates in 4D.  Inspired by Thomas
 Banchoff's book "Beyond the Third Dimension: Geometry, Computer
 Graphics, and Higher Dimensions", Scientific American Library, 1990.
 
-http://en.wikipedia.org/wiki/Real_projective_plane
-http://en.wikipedia.org/wiki/Roman_surface
-http://en.wikipedia.org/wiki/Cross_cap
-http://en.wikipedia.org/wiki/Moebius_strip
+https://en.wikipedia.org/wiki/Real_projective_plane
+https://en.wikipedia.org/wiki/Roman_surface
+https://en.wikipedia.org/wiki/Cross_cap
+https://en.wikipedia.org/wiki/Moebius_strip
 http://mathworld.wolfram.com/RealProjectivePlane.html
 http://mathworld.wolfram.com/RomanSurface.html
 http://mathworld.wolfram.com/Cross-Cap.html