# Simon speaking at the Processing Community Day in Amsterdam

Simon had his first public performance in front of a large audience last Saturday (February 9, 2019): he spoke about his Times Tables Visualization project at the Processing Community Day in Amsterdam!

Simon writes: You can access the code of the poster and the animation (and the logo for my upcoming company!) and download the presentation in PowerPoint, on GitHub at https://github.com/simon-tiger/times_tables

# Simon’s code for an intriguing problem from the 3Blue1Brown math channel

The number of collisions between two objects equals a number of digits of Pi. The code on GitHub: https://github.com/simon-tiger/Pool_Pi

Simon writes:

From where I got this

3rd video: [not out yet]

The idea
The idea is 2 blocks on a frictionless surface. One slides towards the other, that is facing a wall. All collisions are perfectly elastic.

If the two blocks have the same mass, you can quickly calculate that there will be 3 collisions.

If the one block is 100x the other, it just so happens that there will be 31 collisions.

If the one block is 10000x the other, there will be 314 collisions (I get tired of making graphics). If the one block is 1000000x the other, there will be 3141 collisions.

That’s pi!

The issue!
In my own code, I first used Box2D.
It worked for mass ratios of 1 and 100, but it didn’t work for 10000.

Then I started writing my own physics engine, hoping to fix this issue. But it was even worse.
I couldn’t even get 100 to work.

Then I figured that the blocks are colliding too frequently. So I slowed the 1st block down.
I could get 100 to work this way, but not 10000.

Can anybody help to fix this issue?

I borrowed part of the code from here: https://processing.org/examples/circlecollision.html

# Simon’s Times Tables Visualization is Now a Huge Poster!

Simon has made an enormous poster from his earlier animated version of the Times Tables Visualization! Simon is hoping to present this project at the Processing Community Day in Amsterdam in January 2019. The poster is already being printed!

Simon writes: This is a visualization for the times tables from 1 to 200.
Start with a circle with 200 points. Label the points from 0-199, then from 200-399, then from 400-599, and so on (you’re labeling the same point several times).

We’ll first do the 2x table. 2×1=2, so we connect 1 to 2. 2×2=4, so we connect 2 to 4, and so on.

2×100=200, where’s the 200? It goes in a circle so 200 is where the 0 is, and now you can keep going. Now you could keep going beyond 199, but actually, you’re going to get the same lines you already had!

For the code in Processing, I mapped the two numbers I wanted to connect up (call them i), which are in between 0 and 200, to a range between 0 and 2π. That gave me a fixed radius (I used 75px) and an angle (call it θ). Then I converted those to x and y by multiplying the radius by cos(θ) for x, and the radius by sin(θ) for y. That gave me a coordinate for each point (and even in between points, so you can do the in between times tables as well!) Then I connect up those coordinates with a line. Now I just do this over and over again, until all points are connected to something.

Unfortunately, Processing can only create and draw on a window that is smaller than a screen. So instead of programming a single 2000px x 4000px poster, I programmed 8 1000px x 1000px pieces. Then I just spliced them together.

Idea: Times Tables, Mandelbrot and the Heart of Mathematics video by Mathologer
Code: by Simon Tiger

# Creative Coding Utrecht MeetUp

What a blissful day at Creative Coding Utrecht! Simon also got a chance to show a few of his projects in Processing to a cool and understanding audience!

# Optical Illusions in Processing (Java)

Simon created three optical illusions in Processing (Java) playing with color. For better effect, you can download Simon’s code on GitHub: https://github.com/simon-tiger/colorIllusions

The Part 1 video is about the first two illusions. The third (and the coolest) illusion is in Part 2.

Simon writes:
Illusion 1: A checkerboard with blue and yellow squares, but if you move away from it, you see white.
Illusion 2
Mode 1: A disk with red and green, but when you spin it, it becomes yellow.
Mode 2: A disk with red and cyan, but when you spin it, it disappears.
Illusion 3: A rainbow of colors, but when you pause it from flickering, you only see red, green, and blue.

If Illusion 2 Mode 2 doesn’t work, change the background from 255 to between 128 and 135.
If any of the other illusions don’t work, try doing them on a different screen.

Inspired by Physics Girl videos.

# Simon’s Archimedean Solids Project

https://youtu.be/dYBZXFW4bsg

Simon is working on a project that will involve constructing the Archimedean solids from paper pieces that he programs in Processing (Java) and prints out. In the previous video, Simon worked out the distance between two points to measure the side length of a pentagon that has the radius of 1 (i.e. the distance between its adjacent vertices if the distance from its center to its vertices is 1). He first made a mistake in his calculation and got a result that would be true for a hexagon, not a pentagon. He then corrected himself and got the value that he thought he could use in the Processing code, but as it turned out, the ratio between the radius and the side length was still not right. We recorded a whole new video full of calculations and playing with the code, and achieved pretty neat results after Simon used the new value in the code, but still not good enough, as Simon wanted to have his pentagons to have the side length of 40 (to match the triangles and the squares he’d already made). Simon later found a solution using a different formula for a polygon with n sides (from trigonometry, defining the radius as the side length over (2sin times 180/n)) and succeeded in getting exactly the pentagons he wanted, with the side equalling 40. See the result here:

The winning formula:

If you are really into working out the calculations, feel free to check out our frantic attempts here:

https://youtu.be/TuVqc5A08es

# Live Stream #16: Twins Game in Processing and Chapter 6 of Living Code.

Simon’s live stream yesterday had several supportive viewers. Simon started making a game of Twins in Processing (Java) and went on with his JavaScript course Living Code, that is based on Daniel Shiffman’s Nature of Code. He tries to keep his live sessions concise now, no longer than 1,5 hours. Note that in the summer, all the live streams will be in Tuesdays in order not to clash with Daniel Shiffman’s summer schedule.

# Simon’s Times Tables Visualization

Simon shows his Times Tables Visualization in Processing (Java) and talks about how it’s connected to Mandelbrot Set. See the code with the README on GitHub: https://github.com/simon-tiger/times_tables

View the full animation here:

Simon writes: This is a visualization for the times tables from 1 to 200 (including the in-between numbers that are multiples of .01). I used modular arithmetic to write the code:

0. Start with a circle with 200 points (I’ve chosen 200, your number could be anything, but we’ll use 200 in the instructions).

1. Label the points from 0-199, then from 200-399, then from 400-599, and so on (you’re labeling the same point several times).

2. We’ll first do the 2x table. 2×0=0, same thing so we don’t do anything. 2×1=2, so we connect 1 to 2. 2×2=4, so we connect 2 to 4, and so on.

3. 2×100=200, where’s the 200? It goes in a circle so 200 is where the 0 is, and now you can keep going.

4. Now you could keep going beyond 199, but actually, you’re going to get the same lines you already had!

5. You can now create separate images for the 2x table (which we’ve just done), the 3x table, the 4x table, the 5x table, and so on. You can even try in-between numbers (like 2.53) if you want.

In the program, you see an animated image at the left of the screen, and 4 static images (representing examples of times tables) to the right of that. They represent the 2x, 34x, 51x and 99x tables.

The idea of a times tables visualization comes from a video by Mathologer, but the code Simon wrote completely on his own.

# Live Stream #14. 15’s Puzzle Redo continued.

In this live session, Simon continue my 15s puzzle redo live session (“yet again, but I swear this is going to be the last time I do this!” Simon said). Here’s a link to the previous part. This week’s live stream went great, Simon kept it concise, didn’t panic while debugging, largely thanks to a wonderful supportive audience. And he even got some interesting personal questions asked in the end!

# Magic Cards in Base 3!

Simon has developed his version of the Magic Cards, this time in Base 3. He invented this system completely on his own and actually created a program in Processing (Java), using ternary function, to make the cards! The the code for creating the five cards in Processing and exporting the images as png files is available on Simon’s page on GitHub: https://github.com/simon-tiger/browns-criterion-base3

To play the game, have someone think of a number between 0 and 242 and let that person look for his/her number on every card and tell you which colour it is on every card. Every card stands for a power of 3: 81, 27, 9, 3, and 1. There are three grids of numbers on every card, a blue grid (representing the zeros in base 3), a red grid (representing the ones in base 3), and a green grid (representing the twos in base 3). After your friend has found his/her number on all the five cards, you can go ahead and add all the results up to guess the number. Alternatively, if you find working with base 3 too difficult, just sum up all the red numbers in the top left corners (on all the cards where your friend’s number was red), then double all the red numbers in the top left corners (on all the cards where your friend’s number was green) and add all of those together to guess the number.

Simon started out by actually trying to draw the magic cards:

But quickly realised he’s better off writing a computer program to fill in the grids. When the program (pretty tough to write) was finally ready, he tried to print a card out and… ran out of ink on our home printer. Next, we rushed to the print shop, as it was about to close.

“Mom, I can calculate why it says 17 million colours! It’s 256 cubed!” (255 for Red, Green and Blue plus one for alpha).