## Sunday, August 17, 2014

### (5) Logarithmic spiral

( Mathematical software used: gnuplot )

## Sunday, August 10, 2014

### (1) Archimedean spiral: r(θ) = a*θ

(1 < number of spiral turns < 2)

(2 < number of spiral turns < 3)

### (2) Fermat's spiral (Parabolic spiral): r(θ) = a*sqrt(θ)

(1 < number of spiral turns < 2)

(2 < number of spiral turns < 3)

### (5) Logarithmic spiral: r(θ) = a*exp(b*θ)

(b = 0.25)

(b = 0.618)

( Mathematical software used: GeoGebra )

## Friday, August 8, 2014

### Spiral of Spirals

Spirals (green, magenta) around a Spiral Dodecaskelion (grey)

(GIF animation)

A spiral of spirals of spirals.
The spirals are logarithmic spirals: r(θ) = a exp(bθ), b = 0.2.

Spirals of spirals of spirals of ..... (b = 0.2)

A spiral of spirals of spirals.
The spirals are logarithmic spirals with b = 0.30635.

Spirals of spirals of spirals of ..... (b = 0.30635)

Logarithmic spirals
The pair of big spirals: b = 0.1
The small spirals: b = 0.2

The small logarithmic spirals: b = 0.5

The small logarithmic spirals: b = 0.2, 0.5

The small logarithmic spirals: b = 0.5, 0.8

The spirals are Archimedean spirals.
Small spirals: 1 < number of spiral turns < 2

The spirals are Archimedean spirals.
Small spirals: 2 < number of spiral turns < 3

( Mathematical softwares used: GeoGebra, gnuplot )