Coleraine Photos

 Hi

Last weekend was a "Cup Day Long Weekend" (Tuesday holiday, lots of people take the Monday off) in Melbourne and a friend and I headed to Coleraine. My late Mum had lived there, and long after she'd left, my Grandmother Maggie and aunt Lornie lived there. As kids we visited quite often and caught up with various aunts, uncles and cousins on my Mum's side.  

Part of our interest was the rail trail between Coleraine and Hamilton. We both ride bikes!  The trail was quite rugged and muddy after rain. That and the 3k hill on the way out of Coleraine meant the furthest we got was about 5k out of town. However the bikes were ideal pootlers and good for exploring Coleraine, which is a quiet town. There are fewer banks, shops, butchers, pubs and bakeries than there used to be. However there are green shoots with the ever popular chocolate factory a must see. 

Anyway, without really intending to, we visited Lornie and Gran's old farm, Austral Park. Some very nice ladies in the very nice second hand book shop  knew them and Lornie's husband Alan, and not only gave us directions but also rang up Greg who works there, telling him to expect us. We wnt there late on the Monday in the middle of rain showers. 

So lots of photos here, these are mainly for my Cornish cousins. I am now (woohoo) part of their whatsap group.

PS The Coleraine and Dunkeld shps were very accommodating, for example the ops shop opened when some staff were dropping in for a visit, not during official hours at all. We thought we'd missed the op shop but didn't! 

 

 

 

This is a painting I have at home, the house looks different now!

Symmetry and stick polyhedra

Tetrahedron model on a template with a complete set of edges drawn in.

Net of the tetrahedron showing sticks as solid lines, and virtual edges dotted.

Small model tetrahedron with stick model and template for making sides.

Side view.

 

Tetrahedron is a knot made out of an eulerian circuit.

Hi

In the last few days I have been thinking about, and later making some rather minimalist polyhedra which have interesting properties of symmetry. Here is my abstract on these pictures:

"This work shows the construction, form, symmetry and topology of some equilateral -triangle based polyhedra including triangular octahedra, tetrahedra and icosahedra. The polyhedra use craft sticks, drinking straws, and 3d printed jigs at face centres. The constructions depend on rules of face symmetry. Rules for faces of octahedra  - 4 edges join at vertices - vary from those for tetrahedra and icosahedra where 3 and 5 edges join at vertices. Structures take on different forms depending on configuration (side composition and arrangement of pairs of sides) and can be knots from a single Eulerian circuit. Small models of the polyhedra help with visualisation. Curiosity about symmetry led me to explore these shapes, resulting in interesting forms and topologies. 

 Without further ado, here is a brief summary of the pictures.

Tetrahedron

 This was the first model I made, and only one side configuration is available - configurations consist of pairs of sides joined along edges. Placing the shape on the template used to make sides, and marking in other sides helps to identify the shape. 

 

Net for current icosahedron

All the sides before assembly

Icosehedron side view. This is also an Eulerian circuit and knot.

icosahedron top view with model showing configuration of sides

Another view

 

 

Proposed alternative side configuration

Net of alternative configuration

 

Icosahedron

This was the second shape I attempted, and it came together easily and looks interesting - its another Eulerian circuit. One configuration has been made and I've worked out another. 
 

 

Octahedron with one of its sides and a small model showing arrangement of sides. It is made from asymmetrical sides, but by mirroring them as per the net below, the polygon can be formed. 

Octahedron net

 

I believe this is the only other alternate octahedron. It could be made from symmetrical sides but what about asymmetrical sides. Don't know yet!

Octahedron

 

At least one form of octahedron can be made from asymmetric sides. I don't know about the other one but using 2d cad I should be able to find out.

 

That's all for now!