String Figure: Tartoruterjuk
This is a traditional figure of the Arviligjuarmiut people. It is made near Kugaaruk, Nunavut. These instructions were adapted from: Mary-Rousselière, Guy. Les jeux de ficelle des Arviligjuarmiut. Ministère du Nord Canadien et des ressources nationales, 1969 p. 67.
- Form Opening A
- Thumbs picks up radial little finger strings.
- The indices pick up the ulnar thumb strings.
- Left thumb picks up distal radial string from right thumb.
- The right thumb releases its loops, and enters all three left thumb loops from the proximal side.
- The thumbs travel over all the strings and pick up the ulnar little finger string.
- Navaho the bottom three thumb loops.
- The thumbs get the distal ulnar index strings.
- Navaho the thumbs again.
- Release the little fingers.
- The little fingers enter the thumb loops from the proximal side, and catch the transverse string, hooking it to the palm.
- Release the thumbs.
- Navaho the indices and extend.
String Figure: Jackhammer
This figure was invented by Joseph D’Antoni of Queens, New York.
These instructions were adapted from String Figure Magazine Vol.6(4) Dec 2001 p. 15-17.
- Form Opening A
- Release the little loops.
- Rotate the thumb loop away from you, and place it on to the little finger.
- The right thumb enters the index loop from the proximal side and gets the radial little finger string and returns.
- Release the right little finger loop.
- The left index loop is transferred to the left thumb.
- The left little finger loop is transferred to the left index.
- The index loops are rotated towards you on to the thumbs.
- All the fingers enter both thumb loops from the distal side.
- Flex the strings back and forth to animate the Jackhammer
Simple Stop Motion with ffmpeg
Andrew Lindesay has a nice script for simple script for using ffmpeg to do stop motion:
ffmpeg -framerate 10 \
-pattern_type glob -i '*.JPG' \
-vf scale=640:-1 -c:v libx264 -pix_fmt yuv420p \
out.mp4
This works great for compiling photos shot by a GoPro!
The shots are labelled chronologically by frame number:
G0107340.JPG
G0107341.JPG
G0107342.JPG
G0107343.JPG
G0107344.JPG
G0107345.JPG
G0107346.JPG
G0107347.JPG
G0107348.JPG
G0107349.JPG
So, the -pattern_type glob -i '*.JPG'
argument picks them up in order.
The argument scale 640:-1
automatically resizes frames to 640xY and preserves the aspect ratio. This might not be what you want, but it makes for small videos.
Heather Lynn Johnson: Create. Don’t Convert.
Foundational questions:
- What do I want students to learn?
- How can I curate a learning experience that takes advantage of this learning space?
- What is feasible without creating something that is really text heavy?
Museum experience
Teaching playground:
- Introduction (video: learning goals, objectives, human-engagement)
- Investigation (classroom video, geogebra, interaction)
- Reflection (how do I want people to engage with this? what do I want people to notice?)
- Response (to the experience)
Freeze Frame Activity:
- Take a screenshot
- Give a title
- Explain your title / choice
Recognize students device capabilities: phone, computer, etc.
Share directions on how to do stuff
Simplify, simplify, simplify.
Interview with Conway
The Simons Foundation has a lovely series of interview with John Conway.
Lots of stories and insights. He lead a storied life.
PreTeXt on Ubuntu 18.04
As part of the trying out new things bonanza, I installed PreTeXt. It turned out that my install was missing a couple packages: texlive-fonts-extra, texlive-science, and xsltproc.
Once these packages were installed, things worked great!
sudo apt-get install texlive-fonts-extra texlive-science xsltproc
git clone https://github.com/rbeezer/mathbook.git
cd mathbook
git checkout dev
cd examples/minimal/
xsltproc ../../xsl/mathbook-html.xsl minimal.xml
xsltproc -o minimal.tex ../../xsl/mathbook-latex.xsl minimal.xml
pdflatex minimal.tex
P5.js Test-Run
I played around with P5.js today. It is really nice software! There is an in-browser P5.js editor, so you can start playing around instantaneously.
function setup() {
angleMode(RADIANS); // Change the mode to RADIANS
createCanvas(200, 130);
}
function draw() {
background(256);
v1 = [1,0];
v2 = [cos(PI/3),sin(PI/3)];
n=0;
m=0;
while (n <= 5){
while (m <= 5){
p = [20+(20*v1[0]*n)+(20*v2[0]*m), 20+(20*v1[1]*n)+(20*v2[1]*m)]
if ( (n*m) % 2 == 0){
circle(p[0],p[1],20);
fill(200, 0, 0);
} else {
circle(p[0],p[1],20);
fill(0, 0, 200);
}
m += 1;
}
m = 0;
n += 1;
}
}
Bruce and Katharine Cornwell Films
Bruce and Katharine Cornwell produced beautiful animations of mathematics back in the 1960s. I watched the first couple minutes of their film “Possibly So, Pythagoras” (1963) and learned half a dozen pleasant things.
Check out their films, available on Vimeo here.
You can read the memorial from Reed College here.
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