Zeitpyramide: When Maths and Art Disagree

In 1993, the German city of Wemding celebrated its 1200 anniversary.
They decided to start a long-term art project. Every decade, they would place a concrete block on a base. After adding 120 blocks, the pyramid would be complete.


The only problem is that the pyramid will be completed in the year 3183. Which is only 1190 in the future. Not 1200. The project made a basic mathematical error, called the picket fence error. For a picket fence of n elements, you need to have n+1 posts.

Instead of waiting for the first decade to complete before placing the first block, they started immediately. This is like putting the first candle on the birthday cake on your child’s actual day of birth.

Matt Parker pointed out this error during his visit to the placement of the fourth block in 2023. He also proposed an alternative design that would take 121 blocks to complete. Unfortunately, his design is not a pyramid and would be 19.8 meters tall. That is certainly not safe in a storm.


There must be a better design. I took 121 of my beloved LEGO bricks and started on a seven-by-seven base. After some experimentation, I came up with a beautiful pyramid that is only one block taller than the original design. It is still a proper pyramid with complete symmetry.


We can only speculate what Manfred Laber, the artist, had in mind. According to Barbara Schlecht, head of the Zeitpyramide trust, Mr. Laber was fully aware of the consequences of his design. It is certainly much easier to design a sculpture with 120 bricks since it is divisible by 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60 and 120. 121, on the other hand, is only divisible by 1,11 and 121.

When public projects make glaring mistakes, they invite schadenfreude. We can speculate that Manfred Laber decided to sacrifice the opportunity to set a block at the beginning and at the end of the 1200 years period for having a direct relationship between the 120 blocks and the 1200 years.

There are alternative pyramid design for 121 blocks. He could have also decided to only place the foundation in 1993. In any case, this art project has become famous not for its original concepts, but for the controversy around its maths. Which is unlikely to have been the intention of the artist.

Detecting The Corruption Of Online Questionnaires By Artificial Intelligence

Our recent paper on detecting the corruption of online questionnaires by artificial intelligence was recently published in the Frontiers In Robotics and AI Journal. We created a short explainer video about our project:

Here is the abstract of the paper:

Online questionnaires that use crowd-sourcing platforms to recruit participants have become commonplace, due to their ease of use and low costs. Artificial Intelligence (AI) based Large Language Models (LLM) have made it easy for bad actors to automatically fill in online forms, including generating meaningful text for open-ended tasks. These technological advances threaten the data quality for studies that use online questionnaires. This study tested if text generated by an AI for the purpose of an online study can be detected by both humans and automatic AI detection systems. While humans were able to correctly identify authorship of text above chance level (76 percent accuracy), their performance was still below what would be required to ensure satisfactory data quality. Researchers currently have to rely on the disinterest of bad actors to successfully use open-ended responses as a useful tool for ensuring data quality. Automatic AI detection systems are currently completely unusable. If AIs become too prevalent in submitting responses then the costs associated with detecting fraudulent submissions will outweigh the benefits of online questionnaires. Individual attention checks will no longer be a sufficient tool to ensure good data quality. This problem can only be systematically addressed by crowd-sourcing platforms. They cannot rely on automatic AI detection systems and it is unclear how they can ensure data quality for their paying clients.

Peer Review Review

In October 2023 I had the privilege to talk at the Nerd Night in Christchurch. This event series operates at the intersection of comedy, popular culture and science. I talked about my adventures in exploring the peer review process. Some of them to the annoyance of my fellow scientists, conference organizers and predatory publishers. But always with a nod to comic effect and a focus on the overcompetitive beast we call academia.

I also published this event on the HRI Podcast.

Jibo is dead (again)

In 2020 I recorded a podcast episode entitled “Why do all social robots fail in the market?“. I interviewed Tomas Concha from NTT Disruption, the company that had bought the commercially unsuccessful robot Jibo. I already had my doubts about NTT Disruption in 2020. In 2023 NTT Disruption was disrupted. Meaning that it closed down and with it Jibo. This does seem to be the end for this little useless robot.

But don’t worry! Other companies continue to build largely useless robots that are not much more than smartphones on wheels. Have a look at Samsung’s Ballie robot.

The idea of a smart home robot is not new. Amazon developed their Astro robot, but did not sell it to the general public. LG is also presenting a robot at CES2024 with roughly the same features.

I wonder if Samsung or LG will sell their robots to consumers. Or is this just another robot PR gag?