Batch 3 - Class 205 - Planiverse - Astria/Arde
Pre-Class Exercise
(MartinShCol 5.4) An equilateral triangle and regular hexagon have perimeters of same length. If triangle has area of two sq units, what is the area of hexagon?
Answer: 3
Attendanc
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Ayush, Vaazisht, Advay, Arnav, Anishka, Anshi, Siddhant, Aashvi, Rohan, Rhea, Rehaan, Arjun, Angad, SiddharthM, Kushagra
Class puzzles
Review
What is dimension?
How many dimensions does the world around us have?
How do we know?
Is it really three dimensional? Can we describe all coordinates with three dimensions? What are those?
When we see something with our eyes, how many dimensions do we see? By how many independent values can we describe anything that we see?
How about a point on a given straight line - how many variables do we need to exactly describe the point?
How about a point on a plane? On a sphere (back to earth?) In space?
Flatland style planiverse (Edwin Abbott)
Planiverse - Astria (Henton/ Arde Dewdney)
Explain the concept of Planiverse - "on a wall", with gravity
How do people recognize each other?
Full shapes and features, but you could still only see a line
Useful to be able to see on both sides - how would a head "rotate"?
Alternately, you could have one eye on each side, but then you can't see up
What choices exist for eyes?
Lets try and build a full body - what are the considerations?
Hands? Legs?
Can we have muscles to move the "bones"?
What would joints look like?
Can we have an alimentary canal like we have in humans?
No, it would create a "hole" through the body and split it into two
How else can we solve for it? Zipper organs
What other challenges do you foresee in designing a body?
How will people walk? How will they cross each other? Transportation?
One could lie down and the other person can walk over them. But that doesn't scale
One could build footover bridges - try to construct one. Or balloons
How would you make transportation?
You can't use an axle so wheels are hard
Due to gravity, you now have friction, so flat undersides of vehicles won't do
Rolling vehicles are not normally used in Arde
Lets build a house
Overground houses are hard because they would block the way
All houses can be built underground - how will the entrance work?
Swing stairs as a key innovation
Swing Stairs
Water Tank
Collapsible furniture
Lights
No nails and saws, since there is no third dimension
What kind of games could people play?
One dimensional checkers
Two dimensional chess as a more sophisticated design
Orbit of the Planiearth?
Gravity does not decay by square of distance but by distance => circular orbits
No seasons
Sophisticated Machines
Example of Internal Combustion Engine
In 3D world
In Astria
Homework
:
Conceptualize some other interesting machines in Planiverse
References
:
Hinton's Astria
http://www.forgottenfutures.co.uk/flat2/flat2-00.htm
The Planiverse: Computer Contact with a Two-Dimensional World, by A. K. Dewdney
Designs for Planiverse (Arde)
http://cs.stanford.edu/people/eroberts/courses/soco/projects/2005-06/planiverse/designs.html
The Colossal Book of Short Puzzles and Problems, by Martin Gardner