The physical model on the left is a bivariate histogram showing the correlation between the heights of fathers (horizontal axis) and sons ("vertical" axis). This data was famously collected by Karl Pearson and Alice Lee between 1893 and 1898. The physical visualization is thought to have been constructed around this time period or soon after, possibly under the supervision of Pearson. It is kept at the Department of Statistical Science, University College London, founded by Pearson in 1911. I (Pierre) learned about this model after seeing a more recent model in the archives of the collection of solid mathematical models at the Institut Henri Poincaré (right image). A label said "Model Prepared by Dept. of Statistics, University College London". I then wrote to Professor Richard Chandler, current chair of the statistics department, to ask if he had more information about this model. He replied soon after: Thank you for your message below. This is interesting … I have never seen this particular model before, but the labelling looks very similar to some exhibits that were prepared for an event at the Royal Statistical Society in (I think) the 1980s. I arrived at UCL in 1994: at that time there were some people in the department who had been involved in that event. Unfortunately they are no longer with us, so I can’t provide any further information. I can, however, speculate that the model you’re showing is a cardboard copy of a much older one that was prepared at the end of the 19th century, probably under the supervision of Karl Pearson. We still have this. I found this particular model in my desk drawer when I first arrived at UCL: it was broken into a very large number of pieces, but I had it restored. It is quite a nice piece of 19th-century data visualisation, I think! Upon closer examination, the newer model does not show the same dataset as the older model. The following R code replicates the older model exactly, confirming that it shows the original dataset from Pearson and Lee: library(dplyr) library(HistData) library(plot3D) d = HistData::PearsonLee %>% filter(par == "Father" & chl == "Son") %>% reshape2::acast(parent~child, value.var="frequency") plot3D::hist3D(z = d[nrow(d):1,], col="white", border="black", shade=0.2, phi=60, theta=0) Sources: Pearson, K., & Lee, A. (1903). On the Laws of Inheritance in Man: I. Inheritance of Physical Characters. Left photo kindly sent by Richard Chandler. Right photo taken by Pierre Dragicevic during a visit kindly organized by Alba Málaga and guided by François Apéry.

The object on the left may be one of the first sound sculptures. It appears in a 1960 book by German acoustician and musicologist Fritz Winckel (click on the middle image to see the full page). It is a physical 3D spectrogram showing a frequency analysis of an 8-second recording of Beethoven's Eighth Symphony. The left axis is frequency, the bottom/right axis is time, and the vertical axis is the strength of a particular frequency at a particular time. The figure caption uses the term "sonagram", which is how spectrograms were called back in the 1960s. This term originates from the first audio spectrometer called the "Sona-Graph" and commercialized in 1951. The figure caption also uses the unit "kcps" which means kilocycles per second, and is now called kilohertz (kHz). Winckel's book provides no information about the origin of the physical spectrogram, and does not explain how it was built. Nowadays 3D spectrograms are frequently rendered on computers. The video on the right shows an animated 3D spectrogram. Sources: Fritz Winckel (1967) Music, Sound and Sensation: A Modern Exposition, p.76. The original 1960 book is in German, but the scan available on archive.org does not feature the image. Nathan Pieplow (2009) A Brief History of Spectrograms. Wikipedia, Cycle per second.

 Grace Hopper, a computer scientist and US Navy Rear Admiral, used wire to visualise very short durations of time in computing. Each wire is cut to the maximum distance that light or electricity can travel in a nanosecond, one billionth of a second. She wanted programmers to understand 'just what they're throwing away when they throw away a millisecond', and describes using them to help military commanders understand why signals take so long to relay via satellite. This lecture was given at MIT Lincoln Laboratory on 25 April 1985 (video above); she used the short wires as a visual teaching method from the late 60s. A bundle of her nanosecond wires are in the Smithsonian Museum (left photo above). From the Smithsonian Collection Website, under a CC0 license: This bundle consists of about one hundred pieces of plastic-coated wire, each about 30 cm (11.8 in) long. Each piece of wire represents the distance an electrical signal travels in a nanosecond, one billionth of a second. Grace Murray Hopper (1906–1992), a mathematician who became a naval officer and computer scientist during World War II, started distributing these wire "nanoseconds" in the late 1960s in order to demonstrate how designing smaller components would produce faster computers. The "nanoseconds" in this bundle were among those Hopper brought with her to hand out to Smithsonian docents at a March 1985 lecture at NMAH. Later, as components shrank and computer speeds increased, Hopper used grains of pepper to represent the distance electricity traveled in a picosecond, one trillionth of a second (one thousandth of a nanosecond).Reference: Kathleen Broome Williams, Grace Hopper: Admiral of the Cyber Sea, Annapolis, MD: Naval Institute Press, 2004. Grace Hopper (1906-1992) was one of the first programmers of the Harvard Mark I computer, and invented compilers and machine independant programming languages, which underpin most of modern computing. She earned a Ph.D. in mathematics from Yale University and was a professor of mathematics at Vassar College before joining the Navy reserves during World War II. She was behind the development of COBOL in the 1960s; was the first person to use the phrase 'bug' for programming faults, and was posthumously given the Presidential Medal of Freedom in 2016. [Biography summarised from Wikipedia]

Humanity has been gazing at light from distant stars since time immemorial. But in 2015, our ability to understand the University achieved a major milestone, when ripples in Spacetime itself - instead of light - told the tale of an ancient, cataclysmic collision between black holes. The Laser Interferometer Gravitational-Wave Observatory (LIGO) is an experimental system of almost unbelievable sensitivity. Using interferometer arms four kilometers long, it can detect changes in length as tiny as 1/10,000 the width of a proton. Over a billion years ago, two huge black holes, with a combined mass 60 times that of our Sun, spiraled into each other. This event shook the very fabric of space and time, and about three solar masses were converted completely into energy in the form of gravity waves. These waves have been travelling outwards in all directions at the speed of light, until they were noticed by LIGO, on 14 Sept 2015, first at the installation in Hanford, WA, and milliseconds later at Livingston, LA (GW150914). The LIGO team released a 2D spectrogram of the data, showing how the intensity of the gravity waves at different frequencies changed over the course of the event. In this case, the x-axis is time, the y-axis is frequency, and the intensity is indicated by the color. As predicted by Einstein's theory of General Relativity, the coalescing of the black holes involved a "ringdown" increase in intensity of the high-frequency components as they spiraled together faster and faster. I (Louis R. Nemzer) converted this spectrogram into a 3D-printed model. This way, the peak is much more apparent, and the primary signal, as well as the background noise, is much easier to appreciate. This event has paved the way for a new era in astronomy, in which gravity wave signals, along with light, will let us peer deeper into the vastness of Space. Sources: "Gravity Wave Spectrogram" by Louis R. Nemzer hosted on Thingiverse Data from the LIGO Open Science Center