Simon loved the Science Museum, even though he did not get to see the Klein Bottles from the museum’s permanent collection (none of them was on display). He particularly enjoyed the math and information age spaces. The Original Tour was a success, too – giggling at all the jokes on the English audio guide, he was bubbling with joy that he could follow everything and was actively studying the map, together with Dad. The only thing Simon really hated to tears was The Tower.

# Doing Math Everywhere

Doing math everywhere. At the hotel:

At The Tower of London:

Trying to prove the Wallace Product at breakfast:

Coming up with a “spot the mistake proof” at London St.Pancras train station:

# On the train

On the way to London: Simon watching the Coding Train on the train…

And giving his sis an English lesson

On the way back: doing maths under the table

# The skyscraper that set things on fire

Inspired by Matt Parker’s video about the uniquely shaped building at 20 Fenchurch Street in London, Simon was very excited to visit this address. In the video below, made on the pavement in front of the skyscraper, Simon shows the geometric proof (he learned from Matt) of why the building’s shape used to let it set things on fire on extremely sunny days.

# The Maisie Day

For Simon and me, this book (“Infinite Lives of Maisie Day” by Christopher Edge) has probably been one of our most profound experiences of the year. We read it together, sometimes, giggling with joy as we recognized Simon’s favorite topics interwoven in the plot (like that the main character also dreams of proving the Riemann hypothesis), and sometimes tears choking our throats as we went through the sad and scary bits of the story. And what a trip down the memory lane last night, at the Royal Institution in London, where we attended a lecture about the science behind “Infinite Lives of Maisie Day”! As Simon proudly told one of the lecturers (University College London’s cosmologist Dr Andrew Pontzen) after the show, he even predicted something important in the book. Simon recognized that Maisie turned into a mirror image of herself after she had traveled around the Mobius-shaped universe, just as depicted in Escher’s “the impossible staircase” painting . “But that’s only possible if you’re flat, a 2D object! So it’s not correct in the book, but they probably put that in to make it simpler,” Simon laughed. “You’re absolutely right! Keep doing science!” the cosmologist told him. @Ri_Science

# Catenaries

Simon showing us catenaries made of soap, as he brings two plastic bands apart after dipping them in soapy water:

# Evening chess

Playing chess in the park. A beautiful way to spend my birthday evening. The new Chinese chess set was a gift from Steven. To top it all off, Simon also gave me log tables as his last mathematical present tonight!

# Mom is 100111! And she is 33! And 124!

It’s my birthday today and Simon has calculated my age in all the bases up to 20! In the video, he explains what my color is in hexadecimal (base 16), how can turn my age into 33 and why it’s cool to be the age of a Mersenne Prime (so that I start looking forward to turning 63). He also shows a cool way to generate Mersenne numbers, Fibonacci numbers and Lucas numbers.

My birthday in all the bases up to 20 and my colour:

In binary:

In base 5:

Simon’s present: a magic square adding up to 39 in all the rows and columns (and diagonals):

# 2 x 2 x 2 also done!

Completely on his own, without using any YouTube tutorials. (Says he applied parts of the same algorithm as he had learned for the 3 x 3 x 3 one).

# Irrationality of Square Roots

Simon has started a little video series about the Irrationality of Square Roots.

In Part 0, Simon talks about what square root of 2 is and in Part 1, he presents an algebraic proof that root 2 is irrational. He learned this from Numberphile.

In Part 2, Simon presents a geometric proof that root 2 is irrational. Based on Mathologer’s videos.

Parts 3 and 4 following soon!