Crafty, Geometry Joys, Math Riddles, Math Tricks, motor skills, Murderous Maths, Simon teaching, Simon's sketch book

Alternating series, a crafty solution.

What does this infinite sun converge to?
Cut the four L-shapes out…
Divide the central L-shape in four L-shapes and cut those out, too…
You can go on forever…
but it’s already clear at this step, that the sum converges to 2/3 (two of the three squares the original L-shape was made up of)

Simon learned this from an alternating series visualization by Think Twice.

Crafty, Geometry Joys, Math and Computer Science Everywhere, Math Tricks, Murderous Maths, Simon teaching, Simon's sketch book

Area of a dodecagon without trigonometry

How do you find out the area of this dodecagon without using trig?
Rearrange the triangles to make…
Three squares! The area of the dodecagon with a radius r is equal to the area of three r-sided squares or 3r^2.
The formulas for other polygons. There seem to be no formulas for the heptagon, nonagon and hendecagon (without using trigonometry that is). Simon’s notes above also say that no polygon can possibly have an area equal to or larger than πr^2 (because that’s the area of a circle). A square is 2r^2, a dodecagon is 3r^2, and so no polygon is 4r^2.

Simon learned this from a visual mathematics video by Think Twice.

chemistry, Crafty, motor skills, Notes on everyday life, Simon teaching

Messing with the Periodic table

I want to mess with the Periodic Table to see what arrangements I can put it in.

This is called the Wide Arrangement. There are aso a few other arrangements, like the Left Step Wide (or Loop) arrangement, various 3D arrangements (like the ones where you make sure any consecutive numbers are next to each other and it looks like a layered cake).

Although it would be even nicer if we moved H and He over there where they obviously belong.

Spiral periodic table with no gaps between consecutive elements.
You can put it on the top of the Christmas Tree!
Mendeleev’s Flower

Simon learned this from a Minute Physics video.

Crafty, Geometry Joys, Group, Milestones, motor skills, Murderous Maths, Notes on everyday life, Simon teaching, Simon's sketch book

MathsJam Antwerp 18 December 2019

Simon had a wonderful time at MathsJam Antwerp again. One of the problems was something he was already familiar with – the puzzle about hanging a painting using two pegs so that it would definitely fall if one removes any of the two pegs. He explained the way to solve this problem in an abstract way (turning pegs into strings, using knot theory and compiling the algorithm). Later the same evening, he developed a new algorithm to solve the same problem for three pegs and successfully demonstrated the result on his own shoe laces. His solution was the most efficient/ elegant in the group and his enthusiasm was very catchy, the audience said.

In the video below, Simon at first fails to apply his solution correctly, but succeeds upon the second attempt:

Coding, Crafty, Experiments, Geometry Joys, JavaScript, Math and Computer Science Everywhere, Math Riddles, Milestones, Murderous Maths, Notes on everyday life, Simon makes gamez, Simon teaching, Simon's Own Code, Simon's sketch book

Approximating pi and e with Randomness

This has been one of Simon’s most ambitious (successful) projects so far and a beautiful grand finale of 2019, also marking his channel reaching 1K subscribers. The project – approximating Euler’s number (e) in a very weird way – is based upon a Putnam exam puzzle that Simon managed to prove:

The main part of the project was inspired by 3Blue1Brown Grant Sanderson’s guest appearance on Numberphile called Darts in Higher Dimensions, showing how one’s probable score would end up being e to the power of pi/4. Simon automated the game and used the visualization to approximate e. Below is the main video Approximating pi and e with Randomness. You can run the project online at: https://editor.p5js.org/simontiger/present/fNl0aoDtW

Code: https://editor.p5js.org/simontiger/sketches/fNl0aoDtW

The history and the math behind the project:

Simon’s proof od the math behind the project:

Simon has visualized this problem and proof at: https://editor.p5js.org/simontiger/present/2uMPZ8THW

Code: https://editor.p5js.org/simontiger/sketches/2uMPZ8THW

Coding, Crafty, Experiments, JavaScript, Math and Computer Science Everywhere, Milestones, Murderous Maths, Physics, Simon teaching, Simon's Own Code, Simon's sketch book

Galton Board in p5.js

Simon saw a prototype of this Galton Board in a video about maths toys (it works similarly to a sand timer in a see-through container). He created his digital simulation using p5.js online editor, free for everyone to enjoy:

https://editor.p5js.org/simontiger/sketches/h7p-wZCw8

Crafty, Math and Computer Science Everywhere, Math Riddles, motor skills, Murderous Maths, Simon makes gamez, Simon teaching, Simon's sketch book

Proof Visualization. Warning: Mind-boggling!

Inspired by the Card Flipping Proof by Numberphile, Simon created his own version of this proof. He made a solitaire game and proved why it would be impossible to solve with an even number of orange-side-up circles. He drew all the shapes in Microsoft Paint, printed them out and spent something like two hours cutting them out, but it was worth it!

The colourful pieces in the lower row are a “key” to solve the solitaire puzzle. The objective is to remove all the circles. One can only remove a circle if it’s orange side up. Once a circle is removed, its neighbouring circles have to be flipped. Using the key, start with the yellow pieces, and move in the direction of the “grater than” sign (from smallest to largest).

If there’s an odd number of orange circles in the middle, then the end pieces are the same, both orange or both white. In both cases the total number of orange circles will also be odd. If there’s an even number of orange circles in the middle, then the ends have to be different (one orange, one white).

In the case of odd number of orange pieces, the ends have to match. In the case of an even number of orange pieces, you would have pieces that point the same way at both ends. “Now we’ve proven that to make this puzzle possible it has to have an odd number of orange pieces”, Simon says.

Why? Imagine a stick figure that always walks to the right, but always faces in the direction of the arrow (as in it can’t go backwards). It would flip every time it reaches an orange circle. Focusing on everything except the ends, if there are an odd number of orange circles, the puzzle pieces would face the other way. Which means that the end pieces are the same, and therefore the end circles are the same. If there are an even number of orange circles in the middle, the puzzle pieces would face the same way. Which means that the end pieces are different, and therefore the end circles are different.

Simon finds this sort of proof easy, but I felt like my brains are going to boil and dripple through my ears and nostrils. He patently exlained it to me several times and types the above explanation, too.

Crafty, Math and Computer Science Everywhere, Notes on everyday life, Simon makes gamez, Simon's sketch book, Together with sis

Sinterklaas math game with “gingerbread buttons”

It’s Sinterklaas season in the Dutch-speaking world and, of course, as we have started baking the traditional spiced cookies called kruidnoten (“gingerbread buttons”) Simon didn’t want to miss an opportunity to play a version of peg solitaire with eatable pieces!

Simon has baked these himself (together with Neva)
the winning strategy
Simon mixing the right proportion of spices, grinding clove (then adding nutmeg, white pepper, ginger, cardamom and cinnamon)
Computer Science, Crafty, Logic, Simon's sketch book

Simon crafting a search engine with sticky notes

Simon working on a simplified version of a search engine, including just a few documents, and performing calculations to determine how many searches one should do to make creating an index of all the documents efficient (something he has picked up in Brilliant.org’s Computer Science course.

screenshot from Brilliant.org’s Computer Science course