Allschwil Meeting 2018

[Thomas Klemm]

Allschwil Meeting 2018

Introduction
Found this picture in the thread: Nice finding in a drawer.



On 11.10.2015, 01:08 TASP wrote:

Quote:I assume we will have 3D printed reproductions available in a few days.

Goal
2D print a slide-rule for the Pythagorean theorem.

How does it work?
The scale maps a number x to x². Thus we can easily add c² = a² + b².
Then we can map the result back to c.
Or then we can calculate the other cathetus b² = c² - a² given the hypotenuse and one cathetus.

Scales
There are two scales:

• One going from 0-10.
• The other from 0-20.
  

With the upper scale we can calculate: 3² + 4² = 5²
With the lower scale we can calculate: 5² + 12² = 13²

Obviously it's not possible to use this slide rule for all possible combinations.

Quote:For greatest accuracy, use upper scale if possible.

PostScript Documentation

• The red book: PostScript Language Reference Manual
• The blue book: PostScript LanguageTutorial and Cookbook
• The green book: PostScript LanguageProgram Design
• A First Guide to PostScript
• UBC MATH COMPUTING LAB DOCUMENTATION PostScript
• Mathematical Illustrations
• Learning PostScript by Doing
• Postscript Operators
  

GhostScript

Environment
Use ghostscript as a REPL to interactively create the program.

Show the PostScript File

Code:

gs pythagoras-slide-rule.ps

Create a PDF

Code:

ps2pdf pythagoras-slide-rule.ps pythagoras-slide-rule.pdf

Slides

Preparation
To view the slides using vim you need the following settings in your ~/.vimrc file:

Code:

set exrc
set secure

This allows to load the local .vimrc file that maps the left and right arrow keys to :N and :n:

Code:

map <Left> :N<CR>
map <Right> :n<CR>

Start
To start the presentation open all the files:

Code:

cd slides
vim *

Intro
Use the first page to scale your terminal.

Navigation
Use the left and right arrow keys to navigate backwards and forwards.

Exit
To exit the presentation press:

Code:

:q!

Attachment
This is the content of the allschwil-meeting-2018.zip file:

Code:

allschwil-meeting-2018
├── img
│   └── measurement-error-calculator.jpg
├── pythagoras-slide-rule.pdf
├── pythagoras-slide-rule.ps
├── readme.md
└── slides
    ├── 00-intro
    ├── 01-title
    ├── 02-language
    ├── 03-operations
    ├── 04-arithmetic-operations
    ├── 05-arithmetic-operations
    ├── 06-mathematical-functions
    ├── 07-mathematical-functions
    ├── 08-stack-operations
    ├── 09-stack-operations
    ├── 10-comparison-operations
    ├── 11-comparison-operations
    ├── 12-boolean-operations
    ├── 13-boolean-operations
    ├── 14-data
    ├── 15-number.ps
    ├── 16-string.ps
    ├── 17-array.ps
    ├── 18-dictionary.ps
    ├── 19-variables
    ├── 20-global.ps
    ├── 21-local.ps
    ├── 22-control-structures
    ├── 23-conditions
    ├── 24-conditions
    ├── 25-loops
    ├── 26-loops
    ├── 27-while-loop.ps
    ├── 28-greatest-common-divisor.ps
    ├── 29-greatest-common-divisor.rpl
    ├── 30-types
    └── 31-thank-you

2 directories, 36 files

Build Instructions

• Print the pythagoras-slide-rule.pdf file on thick paper. I used A4 160g/m².
• Cut along the three horizontal solid lines. We don't need the top and bottom stripes.
• Fold the wider strip along the dashed lines.
• Flip the folded strip so that the scales are at the top.
• Insert the other strip so that the scales match.
  

It should look somewhat like this:


Kind regards
Thomas