Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: cotpi 69 - Black and white plane
Replies: 26   Last Post: Oct 9, 2013 10:23 AM

 Messages: [ Previous | Next ]
 quasi Posts: 12,067 Registered: 7/15/05
Re: cotpi 69 - Black and white plane
Posted: Oct 2, 2013 3:15 PM

Pubkeybreaker wrote:
>Susam Pal wrote:
>>
>> How can you construct a plane where every point is coloured
>> either black or white such that two points of the same colour
>> are never a unit distance apart?
>>
>> -- Originally posted at:
>> http://cotpi.com/p/69/
>> Puzzles IRC channel:
>> ##puzzles on irc.freenode.net
>> Puzzles IRC webchat:
>> http://webchat.freenode.net/?channels=##puzzles

>
>It does not seem possible. Take any point. Suppose it is
>white. It is the center of a circle (of radius 1). All points
>on that circle must then be black. But given any point on
>that circle there is another point on the circle at distance 1.
>Both points are the same color.
>
>Unless, of course, I am being completely stupid.

quasi

Date Subject Author
10/2/13 cotpi
10/2/13 Pubkeybreaker
10/2/13 quasi
10/2/13 Mike Terry
10/6/13 David Bernier
10/6/13 David Bernier
10/6/13 David Bernier
10/6/13 David Bernier
10/6/13 David Bernier
10/6/13 quasi
10/6/13 quasi
10/6/13 David Bernier
10/6/13 David Bernier
10/6/13 quasi
10/6/13 David Bernier
10/9/13 Phil Carmody
10/9/13 David Bernier
10/2/13 Eric Lafontaine
10/2/13 Michael F. Stemper
10/2/13 quasi
10/2/13 quasi
10/2/13 Haran Pilpel
10/2/13 quasi
10/2/13 quasi
10/2/13 Ted Schuerzinger