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October 8, 2021

A note on "Find the 12 differences"


A couple weeks ago Greg commented, "First time I've gotten them all. Much easier on my iPad!"

I tried doing it on my iPad Pro and got the opposite result: it was very frustrating and difficult compared to doing it on the MacBook Air, so much so that I gave up trying on the iPad and finished it on the Air.

As any fool can plainly see by looking at the photo up top, the puzzle is way bigger on the 12.9" iPad than on the 13.3" laptop.

In fact, while the puzzle appears smaller on my laptop than in the Washington Post magazine IRL, the iPad's image is significantly larger than the dead tree iteration.

I wonder if the fact that my eyes have to move a greater distance from the top panel to the bottom panel each time I make a comparison makes the process more tiring and hence difficult.

Diff'rent strokes.


2018 iPad Pro 12.9": (3rd Gen) 2732p H x 2048p W — 264 ppi

2020 MacBook Air 13.3": 1600p H x 2560p W — 227 ppi

October 8, 2021 at 04:01 PM | Permalink | Comments (0)

'Ask any mermaid you happen to see...'

An earworm of a jingle in a TV commercial that always made me smile when it came on back in the 70s.

October 8, 2021 at 02:01 PM | Permalink | Comments (1)


Almost 4,000 consistently illustrated, modernized emojis that are free to use under Creative Commons.



The way we like it.

October 8, 2021 at 12:01 PM | Permalink | Comments (0)

A solid made of electrons


[This scanning tunneling microscope image of a graphene sheet reveals that a "Wigner crystal" — a honeycomb arrangement of electrons — has formed inside a layered structure underneath.]

From Nature:

Physicists have imaged elusive 'Wigner crystals' for the first time.

If the conditions are just right, some of the electrons inside a material will arrange themselves into a tidy honeycomb pattern — like a solid within a solid. Physicists have now directly imaged these "Wigner crystals," named after the Hungarian-born theorist Eugene Wigner, who first imagined them almost 90 years ago.

Researchers had convincingly created Wigner crystals and measured their properties before, but this is the first time that anyone has actually taken a snapshot of the patterns, says study co-author Feng Wang, a physicist at the University of California, Berkeley. "If you say you have an electron crystal, show me the crystal," he says. The results were published on September 29 in Nature.

To create the Wigner crystals, Wang's team built a device containing atom-thin layers of two similar semiconductors: tungsten disulfide and tungsten diselenide. The team then used an electric field to tune the density of the electrons that moved freely along the interface between the two layers.

In ordinary materials, electrons zoom around too quickly to be significantly affected by the repulsion between their negative charges. But Wigner predicted that if electrons travelled slowly enough, that repulsion would begin to dominate their behaviour. The electrons would then find arrangements that minimize their total energy, such as a honeycomb pattern. So Wang and his colleagues slowed the electrons in their device by cooling it to just a few degrees above absolute zero.

A mismatch between the two layers in the device also helped the electrons to form Wigner crystals. The atoms in each of the two semiconductor layers are slightly different distances apart, so pairing them together creates a honeycomb "moiré pattern," similar to that seen when overlaying two grids. That repeating pattern created regions of slightly lower energy, which helped the electrons settle down.

Graphene Trick

The team used a scanning tunnelling microscope (STM) to see this Wigner crystal. In an STM, a metal tip hovers above the surface of a sample, and a voltage causes electrons to jump down from the tip, creating an electric current. As the tip moves across the surface, the changing intensity of the current reveals the location of electrons in the sample.

Initial attempts to image the Wigner crystal by applying the STM directly on the double-layer device were unsuccessful, Wang says, because the current destroyed the fragile Wigner arrangements. So the team added a layer of graphene, a single-atom sheet of carbon, on top. The presence of the Wigner crystal slightly changed the electron structure of the graphene directly above, which was then picked up by the STM. The images clearly show the neat arrangement of the underlying Wigner electrons. As expected, consecutive electrons in the Wigner crystal are nearly 100 times farther apart than are the atoms in the semiconductor device's actual crystals.

"I think that's a great advancement, being able to perform STM on this system," says Carmen Rubio Verdú, a physicist at Columbia University. She adds that the same graphene-based method will enable STM studies of a number of other interesting physical phenomena beyond Wigner crystals. Kin Fai Mak, a physicist at Cornell University in Ithaca, New York, agrees. "The technique is non-invasive to the state you want to probe. To me, it is a very clever idea."

October 8, 2021 at 10:01 AM | Permalink | Comments (0)

Tetris Micro-Arcade

From the website:

For many people of a certain age, the Game Boy was really just a portable Tetris console with a removable cartridge.


People of all ages will enjoy the endlessly cascading puzzle game in the form of the Tetris Micro-Arcade.

It's a credit card-sized, fully playable version complete with a D-pad, screen, and buttons to rotate and drop your shapes.


The rechargeable dedicated video game is the perfect fit for a shape sorting sesh that doesn't distract you with endless notifications from your news feed.


Features and Details:

• Full-color screen

• 3.25"W x 2"H x 0.25"D

• Sound with toggle switch mute

• Rechargeable Li-on battery via USB Micro



October 8, 2021 at 08:01 AM | Permalink | Comments (0)

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