# Computing with Thread: Part I

## Thread Geometry

We explored what kind of geometric constructions we can do with thread, chalk and the help of several people...

### We found out...

• how to draw a line
• how to draw a circle ( d = const.)
• how to draw an ellipse ( a + b = const.)
• how to draw multifocal ellipses (a + b + c = const.)
• how to draw egg-shaped curves (3 * a + b = const.)
• how to measure the circumference of a circle
• how to calcualte pi using only thread (See also here)

### 3D thread geometry

We explored how our thread-based drawing tools could be used to identify points on the surface of shapes in 3 dimensions.

• We discovered the 3d ellipsoid (a + b = const.)
• We found that multifocal 3d ellipsoids have a doughnut-topology.
• We found two different ways to create ellipsoid shapes:
• the polygon method, where the thread forms a polygon going through the focal points and the drawing point
• the star method where the thread is alternately visiting each focal point and the drawing point

### Observations

• Geometric knowledge from school only got us so far ...
• There is a whole universe of "new" shapes and forms

### Questions raised

• Questions regarding surface of different shapes popped up
• We discussed different methods of measuring the surfaces using thread

### Homework

• What could an Experimentier-Baukasten / a kit / a sandbox for computing with thread look like?
Do some research on other kinds of kits!
• Do some thread-based geometry at home. Pick a parameter such as the thread-length and vary it systematically
• Document your thread-art in the wiki

### Geometry

Some links to classics of compass + straightedge geometry
as well as the thread-based geometry we explored in our class.

### Kitspiration

Here are some links to all kinds of kits.
May they serve as inspiration for creating your own textile computing kits.

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