Tracking Venus and Earth over 8 years

I came about this tweet: It reminded me strongly of the waning moon and linear mod art projects that I’ve been playing with. For instance, here’s a screenshot from the waning moon (specifically y = 56x) A quick intro: the picture above was made by taking 360 points around a circle, and shifting them […]

Big Ice Cubes

Are big ice cubes worth it? Do they dilute your drink slower? Dr. Drang looks at the math behind it.  This needs some more investigation. Also: sphere icecubes.

More pizza?

From a review of a local pizza place: Because of the easily laid out website, I could see that getting three 10-inch pizzas ($6 for plain cheese, $7 for pepperoni, and $9 for a house combo “Carcass” pie with sausage, bacon, pepperoni and meatballs) would result in more pizza and easier-to-handle packaging than adding ingredients […]

Skallops and Regular Polygons

So my skallops arrived and I’ve had some time to play with them. Geometry teacher’s dream. Ok. Will the following setup make a polygon if I keep the same angle and keep adding on? What about 30 degrees? 45, 60, 75, 90, 105, 120, 135, 150, 165, or 180 degrees? Some completed shapes: Square Hexagon […]

Skallops – Geometry Heaven

Skallops are a construction toy that uses laser (no sharks) cut wood clips to put together playing cards. They are up on kickstarter now and they can make some incredible shapes. I just ordered a set myself.

One Zipper Unfoldings of Polyhedra

From Make. Just discovered this fascinating little geometrical recreation at the 2011 Bridges Math Art Conference galleries. The idea is simple, and the field still fairly unexplored, from what I can tell. What interesting 3D shapes can be made by zipping up the edges of a planar shape using a single zipper? A bit of Googling […]

Geometry SBG Concept list

To copy Ms. Nowizee from last year, I want to share my Geometry Concept List. This was the first year of Standards Based Grading in Geometry, and before seeing the end of the year results, I’d give it a B (more to follow). The hard part was designing the list so that each concept was not […]

Scavenger Hunt: Geometry Regents Review

Quick post: In NY our end of the year exam is the Regents exam (no comment). The schedule of the exams this year means that I won’t see my students for 13 days. Great. I made up a Geometry Regents Scavenger Hunt found here: The students solve one set of problems (all the problems […]


From the brilliant(?) minds at, I present to you, the IcoSoKu: Just thousands, that’s it? In my list of mathematical strengths probability does not appear, but there are: 12 unique numbers (vertices of an icosahedron), so 12! = 479,001,600 ways to arrange them. But because of the symmetry involved in a icosahedron, there are 12 ways to […]