# Sam Hartburn

sam@samhartburn.co.uk

# Category: Geogebra

• ## Dancing Triangles: Sunday Maths Animations Week 9

A spiral of dancing trianglesâ€¦just because.

• ## Pythagorean Spiral meets Pursuit Curves: Sunday Maths Animations Week 8

Earlier this week I was proofreading a book that mentioned Pythagorean spirals. I had seen them before but never thought about them too deeply, so I gave them a try in GeoGebra. I filled them in with curves of pursuit, just for fun!

• ## More Cardioid Rainbows: Sunday Maths Animations Week 7

Week 7 of my Sunday Maths Animations is another one that started out as a cardioid. Varying a different parameter gives a completely different effect.

• ## Cardioid Rainbow: Sunday Maths Animations Week 6

Week 6 of my Sunday Maths Animations started out as a cardioid, but quickly became something else.

• ## Pythagorean Tree: Sunday Maths Animations Week 5

Week 5 of my Sunday Maths Animations is a Pythagorean tree, drawn point by point.

• ## Rhodonea Spheres: Sunday Maths Animations Week 4

Week 4 of my Sunday Maths Animations is my old favourite the Rhodonea curve, rendered with spheres. The ending is extremely satisfying!

• ## Infinitely Zooming Circles: Sunday Maths Animations Week 3

Week 3 of my Sunday Maths Animations grew from a puzzle at February’s MathsJam that involved calculating the shaded area in a shape involving infinitely recursing circles. Can you tell which circles are changing in size and which are staying the same?

• ## Circles on a Harmonograph Curve: Sunday Maths Animations Week 2

For week 2 of my Sunday animations I’ve stuck with circles, this time on a harmonograph curve (which is a relation of the Lissajous curves).

• ## Circles on a Lissajous Curve: Sunday Maths Animations Week 1

I’ve been enjoying making animations in Geogebra recently, and have decided to try publising one every week on YouTube. Here is week 1.

• ## Hyperbolic Paraboloid in Matchmakers

For this year’s MathsJam Bakeoff I made a hyperbolic paraboloid out of matchmakers. For anybody who doesn’t know, matchmakers are thin chocolate sticks with crunchy bits, traditionally mint but now available in orange, salted caramel and possibly other flavours. They are delicious even when they are not being used for maths.

• ## Rupert Polyhedra: Dodecahedron

A polyhedron is Rupert if you can cut a hole in it that’s large enough for an identical polyhedron to fit through. I’ve talked about the Rupert tetrahedron, the Rupert cube and the Rupert octahedron. Today it’s the dodecahedron.

• ## Spin, Laugh and Dance

I’d like to introduce you to the graph of $x=\sin(f_1t)e^{d_1t}$, $y=\sin(f_2t)e^{d_2t}$, a curve that spins, laughs and dances.