Simon has been fascinated by these possible-impossible puzzles (that he picked up from the MajorPrep channel) for a couple of days. He prepared many paper visuals so that Dad and I could try solving them. This morning he produced this beautiful piece of design:

# Category Archives: Together with sis

# The Diffe-Hellman key exchange algorithm

This is Simon explaining Diffe-Hellman key exchange (also called DiffeHellman protocol). He first explained the algorithm mixing watercolours (a color representing a key/ number) and then mathematically. The algorithm allows two parties (marked “you” and “your friend” in Simon’s diagram) with no prior knowledge of each other to establish a shared secret key over an insecure channel (a public area or an “eavesdropper”). This key can then be used to encrypt subsequent communications using a symmetric keycipher. Simon calls it “a neat algorithm”). Later the same night, he also gave me a lecture on a similar but more complicated algorithm called the RSA. Simon first learned about this on Computerphile and then also saw a video about the topic on MajorPrep. And here is another MajorPrep video on modular arithmetic.

# Vacation Milestones

A couple more milestones passed! Going on a Ferris wheel after having been afraid of heights for years. “Mom, do you know how many rays there are? I’ll tell you: it’s the only time that exponentiation is commutative!”

Diving deep into the water (after being afraid to put his head underneath the water for years), swimming to the platform in the sea and diving from the platform, using a diving mask.

# My little pure connections to Simon, now 10 years old

What do I love most about Simon’s learning style and being around him are the precious moments he pulls me out of my regular existence, sits me down next to him and shares a piece of his sharp vision with me. I often take notes to make sure I haven’t missed out on the details. Reading back the notes I am often surprised at the hidden layers in his razor-sharp logic that hadn’t revealed themselves to me at first or had even seemed irrelevant to my journalist mind eager to cramp everything to the size of a cocktail bite. Sometimes, Simon takes over and types the rest of the blog entry himself. Like this time.

Dad says he saw someone by the swimming pool reading the book *A Mathematician’s Apology*. We google it and find out it’s a 1940 essay by British mathematician G. H. Hardy about the beauty of pure mathematics. Knowing how much Simon is drawn towards pure mathematics and that he, too, prefers pure mathematics to applied mathematics, I tell him about our discovery. Simon replies that it’s a silly question to ask him whether he knows Hardy: Yes, Hardy was actually the one who invited Ramanujan!

Simon pauses his breadboard tutorial, comes to the balcony with the view across the Cote D’Azur, sits down against the wall of bright purple flowers and patiently tells me an interesting fact about Hardy. It’s just a fleeting tiny conversation, but the beauty of Simon’s precise memory, the connection I feel to Simon and the setting is so striking I would rather grab my video camera but I don’t dare move as not to lose momentum. I later ask Simon to repeat the facts he told me so spontaneously.

“Hardy came up with the total number of chess games. Well, Shannon estimated it to be 10^120, however Hardy estimated it to be 10^…, 10^50.

Clarification: the former is:

1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000

(1 with 120 zeros)

And the latter is:

1 with 100 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 zeros

(1 with, a 1 with 50 zeros, zeros)

# Some more London

# On top of The Shard, the tallest building in the EU

A real victory for Simon, who has had a bit of a fear of heights for years. But what he found most impressive were the noticeable changes in gravity while going up and down with the elevator. When descending from the 72nd floor he could feel the decreased G!

# The Camera Obscura at the Royal Observatory in Greenwich

# We’ve found the real 0° meridian!

And it turned out to be a that little path next to the Royal Observatory in Greenwich, not the Prime Meridian line. The 0° meridian is what the GPS uses for global navigation, the discrepancy results from the fact that the Prime Meridian was originally measured without taking it into consideration that the Earth isn’t a perfect smooth ball (if the measurements are made inside the UK, as it it was originally done, this does’t lead to as much discrepancy as when vaster areas are included).

# All Nerds Unite: Simon meets Steve Mould and Matt Parker in London

Hilarious, inspirational and loaded with cosmic coincidences, this was one of the best evenings ever! Many of our currently favourite themes were mentioned in the show (such as the controversy of Francis Galton, the BED/ Banana Equivalent Dose, sound wave visualizations, laser, drawing and playing with ellipses, Euler’s formula). Plus Simon got to meet his teachers from several favourite educational YouTube channels, Numberphile, StandUpMaths and Steve Mould.