Linkfest, part 2

(Saved from the drafts bin...)

• These gifs are making the rounds on Facebook. I'm putting the link here so I can find them later.
• Henry Segerman makes fascinating mathematical artwork using 3D printing. While honing the description of the piece we'll be featuring in Playing with Math, I can across his 100 prisoners and a lightbulb paper. The puzzle posed seems impossible, but...
• Here's a much easier puzzle from 9gag (found on Facebook).