In 1920, after Lenin delivered a speech in Petrograd to troops departing to fight in the Soviet-Polish war, Russian artist El Lissitzky challenged his architecture students to design a speaker’s platform on a public square. The result was the Lenin Tribune, a rostrum that can bear its speaker aloft to address a crowd of any size. In a letter to the art historian and critic Adolf Behne, Lissitzky wrote:

I have now received some sketches of former works and have reconstructed the design. Therefore I do not sign it as my personal work, but as a workshop production. The diagonally-standing structure of iron latticework supports the movable and collapsible balconies: the upper one for the speaker, the lower one for guests. An elevator takes care of transportation. On top there is a panel intended for slogans during the day and as a projection screen at night. The gesture of the entire speaker’s platform is supposed to enhance the motions of the speaker. (The figure is Lenin.)

Here the message reads PROLETARIAT. Lissitzky later said he regretted not publishing the design when Vladimir Tatlin’s Monument to the Third International was attracting attention, so that the two might have competed against one another.

The Oxford Electric Bell

Images: Wikimedia Commons

The University of Oxford has a bell that’s been ringing almost continuously since 1840. A little 4-millimeter clapper oscillates between two bells, each of which is positioned beneath a dry pile, an early battery. Due to the electrostatic force, the clapper is first attracted to and then repelled by each bell in turn, so it’s been ringing them alternately for 179 years. The operation conveys only a tiny amount of charge between the bells, which explains why it’s managed to run so long. The whole apparatus is kept under two layers of glass, but the ringing is so faint that it would be inaudible in any case.

It’s estimated that the bell has produced 10 billion rings so far — it holds the Guinness World Record as “the world’s most durable battery [delivering] ceaseless tintinnabulation.”

In and Out


The briefest interview I’ve ever conducted was with Renato Dulbecco, who has since shared in a Nobel Prize for work in animal-cell culture and tumor viruses. Through his secretary, we had made an appointment. When I reached his office, he ushered me in, closed the door, sat down at his desk — and said that he was not going to talk to me. Startled, but respecting him at least for not having imposed on his secretary the task of rejection, I said something about the importance of getting scientific work across to the general public. Dulbecco replied, ‘We don’t do science for the general public. We do it for each other. Good day.’

— Horace Freeland Judson, “Reweaving the Web of Discovery,” The Sciences, November/December 1983

(“I thanked him for the interview and left, promising myself to use it someday. He was correct, of course, though unusually candid.”)

Black and White

van dehn chess puzzle

A remarkable thematic chess puzzle by Bodo Van Dehn, 1951. White to move and win.

The solution is 10 moves long, but all Black’s moves are forced. (That’s a very valuable hint.)

Click for Answer

Good Fortune

Letter from Albert Einstein to J.E. Switzer, April 23, 1953:

Dear Sir

Development of Western Science is based on two great achievements; the invention of the formal logical system (in Euclidean geometry) by the Greek philosophers, and the discovery of the possibility to find out causal relationship by systematic experiment (Renaissance). In my opinion one has not to be astonished that the Chinese sages have not made these steps. The astonishing thing is that these discoveries were made at all.

Sincerely yours,

A. Einstein


walkington knight diagonals
Image: William Walkington (CC BY-NC-SA 4.0)

The “Lo Shu square” is the 3 × 3 square enclosed in dashed lines at the center of the diagram above. It’s “magic”: Each row, column, and long diagonal (marked in red) sums to 15. William Walkington has discovered a new magic property — imagine rolling the square into a tube (in either direction), and then bending the tube into a torus. And now imagine hopping from cell to cell around the torus with a “knight’s move” — two cells over and one up. (The extended diagram above helps with visualizing this — follow the blue lines.) It turns out that each such path touches three cells, and these cells always sum to 15. So the square is even more magic than we thought.

More info here. (Thanks, William.)

Podcast Episode 261: The Murder of Lord William Russell

Image: Harvard Digital Collections

In May 1840 London was scandalized by the murder of Lord William Russell, who’d been found in his bed with his throat cut. The evidence seemed to point to an intruder, but suspicion soon fell on Russell’s valet. In this week’s episode of the Futility Closet podcast we’ll follow the investigation and trial, and the late revelation that decided the case.

We’ll also marvel at Ireland’s greenery and puzzle over a foiled kidnapping.

See full show notes …

Revere’s Obelisk

revere's obelisk

To celebrate the repeal of the Stamp Act, Paul Revere designed an obelisk that was erected on Boston Common on the evening of May 22, 1776. Its four panels, painted on translucent waxed paper borne on a wooden frame, described the phases of the struggle against the act:

1. America in distress apprehending the total loss of Liberty.

2d. She implores the aid of her Patrons.

3d. She endures the Conflict for a short Season.

4. And has her Liberty restord by the Royal hand of George the Third.

At the bottom is the legend “To every Lover of Liberty, this Plate is humbly dedicated, by her true born Sons, in Boston New England.”

It was illuminated by 280 candles, and fireworks and Catherine wheels were launched from its sides. Unfortunately it “took Fire … and was consumed” a few hours a later. This is the only surviving copy of the engraving.

(Thanks, Charlie.)

A Flea’s Journey

Image: Wikimedia Commons

A flea sits on one vertex of a regular tetrahedron. He hops continually from one vertex to another, resting for a minute between hops and choosing vertices without bias. Prove that, counting the first hop, we’d expect him to return to his starting point after four hops.

Click for Answer