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Posts by Michael Borcherds

Barney Maunder-Taylor says a square-based pyramid is exactly twice the volume of a triangular-based one (same side length). He doesn't want the tedious trig approach to proving it though, he wants a more intuitive route. He'll try the usual proof by @geogebra.org instead #mathsjam

4 months ago 3 3 0 0
Welcome to AMiE
Welcome to AMiE YouTube video by Association for Mathematics in Education (AMiE)

📣 We’re excited to welcome you to the newly formed Association for Mathematics in Education!

After bringing together five long-standing associations, we’re proud to unite our communities, expertise, and energy under our new association.

Watch our welcome video: www.youtube.com/watch?v=1uLL...

4 months ago 11 10 0 0

We’re looking forward to seeing everyone at MathsJam Gathering this weekend - follow along here to see what people are sharing, and use #mathsjam to share your favourite moments!

5 months ago 2 1 0 0

After some confusing back and forth interactions, I've realized that "I moved the meeting back by 30 min" is interpretable as both:
- "moved earlier by 30 min", and
- "moved later by 30 min"

5 months ago 8 1 1 0

Works nicely, very cool 🙏🙏🙏

5 months ago 0 0 0 0
Preview
Third of a cube (assemblable, with clearance) - Download Free 3D model by robinhouston This is exported from BurrTools with the following parameters: Unit size: 10.00 Bevel: 0.30 Offset: 0.1 Wall Thickness: 0.00 Tubes size: 0.05 Leave inside grooves: no Leave outside grooved: no Remove grooves in void: no - Third of a cube (assemblable, with clearance) - Download Free 3D model by robinhouston

If anyone wants to try printing this and testing it in the real world, the model here might be more suitable: it has slightly rounded edges, and the faces are slightly inset to give more clearance when assembling it. https://skfb.ly/pzDKY

8 months ago 0 1 1 0
Preview
Five Fit - Tray-packing puzzle by Stewart Coffin (STC #177-A) by asiegel Five FitTray-packing puzzle by Stewart Coffin (STC #177-A)Fit all five pieces into the square opening.Five Woods is one of a series of tray-packing puzzles by Stewart Coffin. It seems impossible at fi...

Did you solve it? Looks interesting!

This one is very good, also by Stuart Coffin www.thingiverse.com/thing:3433358

5 months ago 0 0 0 0
A photograph of a tray-packing puzzle, showing a tray containing three pentominos with a fourth pentomino separately. The puzzle is to fit all four into the tray.

A photograph of a tray-packing puzzle, showing a tray containing three pentominos with a fourth pentomino separately. The puzzle is to fit all four into the tray.

I spent hours yesterday (on a long plane journey) failing to solve Stewart Coffin's Four Fit puzzle. I tried everything I could think of, and nothing worked.

If you know the solution please don't tell me.

8 months ago 0 1 4 0
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Original post on mathstodon.xyz

// Here is some OpenSCAD code, if you want to understand how I made it, or to make your own:

r = 10;
h = 60;

module hex_prism(i) {
rotate([acos(1/sqrt(3)), 0, i * 90])
linear_extrude(height = h, center=true)
circle(r, $fn=6);
}

for(i=[0 : 1 : 3])
for(j=[i + 1 : 1 : 3])
for(k=[j + 1 : 1 : 3]) […]

6 months ago 0 1 0 0
A pile of small white plastic pieces, tetrahedral with protruding pegs and holes so they can be joined to each other

A pile of small white plastic pieces, tetrahedral with protruding pegs and holes so they can be joined to each other

The first prototype came out better than I expected, though there's a lot of room for improvement still.

6 months ago 1 1 2 1

Thanks, it prints really nicely without supports 😮😮😮
(on P1S)

5 months ago 1 0 0 0
Close up of side of turquoise noperthedron on a table. The shape is turquoise with triangulation where the band around it Center has smaller triangles and the top and bottom have longer triangles creating a belt around it that is more bulbus.

Close up of side of turquoise noperthedron on a table. The shape is turquoise with triangulation where the band around it Center has smaller triangles and the top and bottom have longer triangles creating a belt around it that is more bulbus.

A turquoise 3d printed  bulbous triangulated vase on a table with some rocks and weaving.

A turquoise 3d printed bulbous triangulated vase on a table with some rocks and weaving.

A noperthedron container printed!

#mathart #mtbos #noperthedron #polyhedra

7 months ago 51 8 3 4

Link is 404 for me 😭

5 months ago 0 0 0 0
A teal noperthedron with a cylindrical hole in a drafting program with shadowing. The shape is vase-like with triangulated faces, but bulbous at the center and slanted inward at the top in bottom so that there is a band of 3 layers of shorter triangles in the middle and longer more angled-in triangles at the top and base of the vase (container).

A teal noperthedron with a cylindrical hole in a drafting program with shadowing. The shape is vase-like with triangulated faces, but bulbous at the center and slanted inward at the top in bottom so that there is a band of 3 layers of shorter triangles in the middle and longer more angled-in triangles at the top and base of the vase (container).

I am printing a noperthedron pencil holder :)

#mtbos #mathart #noperthedron

7 months ago 88 14 3 1
Video

Patrons de pyramides "coupées" par un plan.

#geogebra : www.geogebra.org/m/kjmjkmkj

#math #pyramid #net #geometry #patron

1 year ago 4 1 0 1
Un rouleau de papier toilette incroyablement modélisé dans Geogebra.

Un rouleau de papier toilette incroyablement modélisé dans Geogebra.

- Tu sais utiliser Geogebra ?
- Oui, bien sur. Je l'utilise tout le temps pour réaliser des figures de géométrie un peu difficiles.

Mon utilisation réelle de Geogebra :

7 months ago 25 2 2 0

Yes to everything that has already been mentioned. Additionally, I use some geogebra constructions as well (especially for linear optics, nice interactive demos for images from lenses, and multi-sense-systems)

7 months ago 1 1 1 0
Video

La Esfenocorona es un poliedro convexo con 12 △ equil. y 2 □, 22 aristas y 10 vértices. De estos, en 2 inciden 2 △ y 2 □, en ese orden; en 4 inciden 3 △ y un □; en los 4 restantes 5 △. Es el sólido de Johnson J86.
#GeoGebra
ilarrosa.github.io/GeoGebra/Esf...
ilarrosa.github.io/GeoGebra

6 months ago 2 2 0 0
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Oh, also peterkagey.com/assets/blog/... is 404

6 months ago 0 0 1 0

Thanks so much 🙏🙏🙏

Please check, piece 7 seems to be 404 peterkagey.com/assets/blog/...

6 months ago 0 0 1 0
Preview
Pentagonal icositetrahedron puzzle A puzzle on the faces of the pentagonal icositetrahedron with 3D models, STL files, photos, and video illustrations

Sure thing! I wrote a blog post just for you which includes links to the STL files.

6 months ago 2 1 1 0

In-person tickets are selling fast for the MathsJam UK Gathering - join us (in-person or remotely!) for a weekend of recreational maths in a conference centre and meet others who also love maths! Details at www.mathsjam.com/gat...

6 months ago 0 1 0 0

As well as our monthly pub meetings, there are also bigger annual MathsJam gatherings - one in the UK around November, and one in Oceania (New Zealand) - for details visit https://mathsjam.com/gathering

6 months ago 0 1 0 0
Video

Tomorrow in Cal: The amazing e^x whose derivative is e^x. @geogebra makes these visuals so easy.

5 years ago 0 1 0 0

I've been seeing ads for the Shashibo toy. It looked like a more elaborate version of the kaleidocycle, which is fun to make out of paper. Shashibo is a ring of pyramids that comes in the shape of a cube but can be rearranged into a variety of shapes....

3 years ago 2 1 1 0
The 'net' of a Polyhedron as a Stereographic Projections - TMIP Animation Challenge
The 'net' of a Polyhedron as a Stereographic Projections - TMIP Animation Challenge YouTube video by Ben Cornish

Hello @tmip.bsky.social et al.

Let me introduce my submission for the April Animation prompt of a 'Polyhedral Net'. I went with the type used for fishing, I hope you enjoy it.

#geogebra #mathanimations #mathsky #mathsanimationtmip

youtu.be/fCtsAXOo4NU

1 year ago 5 3 0 0
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#PythonGgb : courbe de Gosper, un poil plus alambiquée que la ligne de Hilbert...
Défi personnel, mais peu de plus value didactique par rapport aux usages séparés de #python et de @geogebra.
En classe, moins de spectaculaire, mais plus de géométrie dynamique !
geogebra.org/python/index...

2 years ago 3 2 0 0
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I made this @geogebra applet that lets you play with Johan Gielis's polar super-formula. You can use it to make interesting shapes like these. https://www.geogebra.org/m/pprqzpja

6 years ago 1 1 1 0
¿Hasta dónde podemos llegar con GeoGebra?

¿Hasta dónde podemos llegar con GeoGebra?

Xa podemos empezar a desvelar cousiñas... <<¿Hasta dónde podemos llegar con GeoGebra?>> é o título da ponencia coa que nos vai deleitar @bancoche.bsky.social no IV Día GeoGebra de Galicia.
#ourense #15febreiro #diageogebragalicia @geogebra.org

1 year ago 5 8 0 0
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Klein Bottle exploration in #GeoGebra #3d calculator with AR: youtube.com/shorts/NDXlX...

11 months ago 4 2 0 0