Comics
– These comic strips are the property of their respective owners, namely PHDcomics.com, xkcd.com, and AbstruseGoose.com.
– Displaying these strips here doesn’t necessarily imply my advocacy of the relevant matters.
Gource, Software Version Control Visualization Tool
Feynman, Laws of Physics and Rules of Chess, An Analogy
Nature by Numbers
Getting Git by Scott Chacon
[Voiceover of the slides http://blip.tv/file/4094854]
[ProGit Book]
[Git Reference]
Peter Alfeld-Nick Trefethen $100 bet
[From http://www.math.utah.edu/~alfeld/bet.html]
Moebius Transformations
A short film depicting the beauty of Moebius Transformations in mathematics. The movie shows how moving to a higher dimension can make the transformations easier to understand.
[From http://www.ima.umn.edu/~arnold/moebius]
Heine-Borel Theorem
This video illustrates a proof of the Heine-Borel Theorem: “Every closed bounded set in 
[From http://www.calendar.algebraicsurface.net]
Compactness and Stereographic Projection
In this video the stereographic projection of the sphere to the plane is illustrated. Also a proof that the plane is not compact is shown.
[From http://www.calendar.algebraicsurface.net]
Laser Helix
From DrWurm:
A light ray enters the edge of the plastic. It travels through the plastic until it comes to the junction between the air and cylinder. Because of the small angle the light makes with the cup, instead of going through the junction and refracting, it reflects back in to the plastic. After reflecting, the ray hits another junction and reflects again. This process contains the light within the plastic as it continues on its initial downward direction, creating the helix you see. This is the same principle that fiber optics use to transmit light through non-linear paths.
George Dyson, Birth of the Computer
[The figure shows an Electrical Model illustrating a Mind having a Will but capable of only Two Ideas.]
The History of Mathematics
[This series was once removed from YouTube on the basis of "Copyright infringement." Watch it before it's too late.]
GPU versus CPU
Steven Strogatz on Sync
Eric Mazur on Interactive Teaching, Peer Instruction, Active Engagement, and Motivation [Thanks to Walking Randomly for posting about this.]
Gilbert Strang “executing” a determinant formula
Conway’s Game Of Life in APL [Thanks to Matt McDonnell for posting about this in Mathematical Recreations: Tweetable Game Of Life.]
[More details on this may be found in Dyalog.]
[Picture from Gilbert Strang's homepage]
[Image from lbrandy]
Timothy Gowers: The Importance of Mathematics
[Playlist of all parts]
[Transcript of the lecture (slightly modified)]
Optical Illusion
The squares marked A and B are the same color.
See the proof because, unless your visual system is malfunctioning, you MUST see them of different colors! Here is an interactive proof.
Here is an explanation by the inventor of the illusion Edward H. Adelson:
The visual system needs to determine the color of objects in the world. In this case the problem is to determine the gray shade of the checks on the floor. Just measuring the light coming from a surface (the luminance) is not enough: a cast shadow will dim a surface, so that a white surface in shadow may be reflecting less light than a black surface in full light. The visual system uses several tricks to determine where the shadows are and how to compensate for them, in order to determine the shade of gray “paint” that belongs to the surface.
The first trick is based on local contrast. In shadow or not, a check that is lighter than its neighboring checks is probably lighter than average, and vice versa. In the figure, the light check in shadow is surrounded by darker checks. Thus, even though the check is physically dark, it is light when compared to its neighbors. The dark checks outside the shadow, conversely, are surrounded by lighter checks, so they look dark by comparison.
A second trick is based on the fact that shadows often have soft edges, while paint boundaries (like the checks) often have sharp edges. The visual system tends to ignore gradual changes in light level, so that it can determine the color of the surfaces without being misled by shadows. In this figure, the shadow looks like a shadow, both because it is fuzzy and because the shadow casting object is visible.
The “paintness” of the checks is aided by the form of the “X-junctions” formed by 4 abutting checks. This type of junction is usually a signal that all the edges should be interpreted as changes in surface color rather than in terms of shadows or lighting.
As with many so-called illusions, this effect really demonstrates the success rather than the failure of the visual system. The visual system is not very good at being a physical light meter, but that is not its purpose. The important task is to break the image information down into meaningful components, and thereby perceive the nature of the objects in view.
Haze Illusion
[Flash movie by Meredith Talusan based on a paper by Edward H. Adelson. More optical illusions at http://web.mit.edu/persci/gaz]
1999 A.D. (Shopping from Home)
A clip from the 1967 film 1999 A.D. in which the family of the future is shown shopping, paying bills, and using “email” from home.
[For a collection of past visions of the future, visit Matt Novak's Paleo-Future.]
