# Jeff Thompson | Blog

## Cat metronome

A cat metronome made by Wittner Taktell.

April 28th, 2010 at 4:25 pm

## “Season of the Witch”

An amazing and weird version of “Season of the Witch” by Julie Driscoll and Brian Auger’s Trinity on an episode of Peter Cook and Dudley Moore’s “Goodbye Again” in 1968.

April 27th, 2010 at 4:22 pm

## Paint bucket tool and web surfing

[ two animations of Flood Fill algorithms by Andre Karwath ]

It turns out that two things are true:

1. Shopping at McMaster Carr can actually be good research
2. The Paint Bucket tool in Photoshop and web surfing are quite similar

Too complicated to explain why, but the McMaster site led me to Dijkstra’s algorithm, a method for determining the shortest distance between two points within a graph of many points.  Below is an animation by Steven Skiena showing the algorithm:

Dijkstra’s algorithm is used for sending packets over the internet (finding the shortest path of cable to send information) and possibly for route finding on Google Maps (pure conjecture).

The Paint Bucket uses a related algorithm called Flood Fill, Seed Fill, or Boundary Fill.  The animations at the top of the post show Flood Fills that look in four directions (left) and eight (right).  There are lots of other variations of the Flood Fill that work in different ways, mainly in how many times they repeat pixels.

The actual implementation of the algorithms is way beyond me, but the connection between routing of information and drawing in the computer is fascinating.

April 27th, 2010 at 11:19 am

## Shortest Path on the Surface of Convex Polyhedron

“Shortest Path on the Surface of Convex Polyhedron” by Joseph O’Rourke at Smith College.

April 26th, 2010 at 6:02 pm

## Convex Hull Of 1000 Random Points on a Sphere

“Convex Hull Of 1000 Random Points on a Sphere” by Jon McCammond of the Mathematics Department at UCSB.

April 26th, 2010 at 5:59 pm

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## Unexpected GarageBand icons

In a hunt for interesting Mac sounds, graphics, etc I opened the GarageBand package contents (right-click on the application icon, show package contents, and all pieces will be in the “Resources” folder).  Buried within the tiny guitars and flutes are the above weird images.  A Google search returns nothing about these.  Maybe some hidden military instruments?

April 24th, 2010 at 4:47 pm

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## 4d Hypercube and 5d Penteract

Computer animated movie of a rotating four-dimensional hypercube, perspectively projected into 3D as stereoscopic left and right images, to be viewed cross-eyed. The computer animation was performed at Bell Labs in the mid 1960s. This is one the first stereoscopic digital computer animations. The image quality became degraded during the process in which the original 16-mm film was digitized.

April 23rd, 2010 at 2:15 pm

## Unknown German video game

Unknown German tech demo/game from around 1994. Think I got it off a cover disc or a PD disc?”  Runs on the Acorn system.

April 23rd, 2010 at 2:12 pm

## Photograph of a revolution

An image of revolution actually happening.  While looking for images of the shapes of demilitarized zones for unrelated reasons, I found this image of the “Storting” in Norway.  According to the Wikipedia text:

In early 1905, Christian Michelsen formed a coalition government consisting of liberals and conservatives, whose only stated objective was to establish a separate Norwegian corps of consuls. The law was passed by the Norwegian parliament. As expected and probably as planned, King Oscar II refused to accept the laws, and the Michelsen government resigned. When the king declared himself unable to form a cabinet under the present circumstances, a constitutional crisis broke out on 7 June 1905… Initially reacting to this declaration as a rebellious act, the Swedish government indicated an openness to a negotiated end to the union, insisting among other things on a Norwegian plebisciteThe plebiscite was held on 13 August and resulted in an overwhelming 368,208 votes (99.95%) in favour of dissolution against 184 (0.05%) opposed.

While there are lots of images of revolutionaries and events that consitute revolutions, my non-expert guess is that there are almost no photographic images of a revolution in its entirety.

Image via: Wikipedia user Leifern.

April 22nd, 2010 at 6:51 pm

## Toroidal internal combustion engines

A toroidal internal combustion engine made by Rotoblock.

Via: Rotoblock, after finding a similar engine in the excellent “The How and Why of Mechanical Movements” by Harry Walton.

April 22nd, 2010 at 6:09 pm