Airport luggage cones

Found these beauties at the airport. My theory is that they have something to do with luggage transport.

Wintry Moiré

I saw an awesome Moiré pattern, formed from two perforated sheets of metal at slightly different distances from the camera. This gives a slight size difference, and therefore a slight frequency mismatch for the two sheets. It's nice how the original hexagonal pattern of the holes is repeated, hugely, in the Moiré pattern (much nicer than the boring examples on Wikipedia)!

Nut Domains

The square nuts from our Meccano set. Pushed together randomly, they form nice orientation domains - little areas where each square lines up with its neighbors.  Gaps open up between these domains, since they are not  lined up with each other.

The pattern reminds me of a city map, where rectangular buildings on a block are lined up, and then at a bigger street, the angle changes.

Iridescent frying pan

Our stainless steel frying pan with colorful patterns. Frying stuff in this pan is not particularly nice, since everything, including bacon, seems to stick unless I add lots of fat. The colors offer some consolation, though. I suspect these colors appear due to light interference in a thin film of oxide on the pan's surface.


This picture of a Bismuth crystal from Wikipedia shows the same effect. The crystal is covered with a thin oxide layer. When light reflected from the top and bottom of the oxide layer interfere, the colors appear. I like the G-shaped growth patterns in this picture even more than the rainbow coloration.

WiFi screen

We live on the edge of wireless reception. Even with an external antenna in the window, the signal was not quite strong enough and the connection was frequently dropped. Our friend Halza had the idea to use a strainer as a reflector. This trick works great for us too, and improves the reception considerably.
The WLAN antenna inside the strainer is one of these.

The WLAN signals are in the 2.4 GHz band, which means that one wave length is 12.5 cm. Already a reflecting plane, placed 1/4 wavelength (3.1 cm) behind the antenna should provide constructive interference and some signal gain. A parabolic reflector with the antenna in the focal point provides more. The strainer not exactly a parabola, but has the right general looks.

Lots of variants on this idea are available.

Cyborg bread

Sometimes, bread machine parts are left inside the finished product.

Beaded bowl surfaces

Hexagons side by side forms a flat surface, with zero curvature. Reading Make Magazine's Math Monday, I learned that a pentagon among the hexagons makes the surface  curvature positive, like the surface of a sphere. A heptagon does the opposite - it creates a saddle surface, which has a negative curvature.

Here, I've built the same bowl-shaped trial surface from white glass beads and from Magnetic spheres. The surface is formed from hexagons, with a pentagon in each 'corner', to make the surface curve.

In an earlier post, I used only pentagons, which shapes the surface into a sphere.

Drops in sink

Street Things Marburg, Part Two

Street Things Marburg, Part One

Street Things Turku, Part Two

Tiny, feeble measuring points. Approximately natural size.

Street Things Turku, Part One: Round Covers

Life

A walking Meccano elephant!

Magnetic Dodecahedron

Magnetic spheres forming a dodecahedron. Made from twelve five-sphere rings. The rings turn into five-sided polygons when placed side by side in the dodecahedron - this is seen with a flux detector (right).

 A larger one, made from ten-sphere rings.

The largest one I could make with my set, with fifteen-sphere rings. The dodecahedron was still surprisingly stable, but softer, like an over-ripe orange.

Shiny and New

Ordered some new polymer clay tools from a German online polymer store - a Kemper needle tool, a ripple blade, and a set of tiny 5 mm (5/16 in) Kemper shape cutters.

Street Things Belgium, part three

Part of the Atomium.

Street Things Belgium, part two

Street Things Belgium, part one

Street View Netherlands, part two

 Some more of these street objects, from our recent trip to the Netherlands...

...and some uncategorized bonus objects, such as some surprisingly pretty moss between paving stones. I'm guessing "hond in de goot" means that dogs are not allowed in some store nearby. The red-and-yellow graphics was lighted up at night, and depict the bombing of Rotterdam. The silhouette is of a Rotterdam statue which also commemorates this.

Street View Netherlands, part one