import settings;
import graph;
import math;
 
 
pdfviewer="/usr/bin/evince";
psviewer="evince";
 

// parameters

int num=10;
 
 
int gcd(int a,int b){
	if(b==0){
		return a;
	}else{
		return gcd(b,a-quotient(a,b)*b);
	}
}
bool isPrimeWith(int a,int b){
	return gcd(a,b)==1;
}

 
pen color_rational(int x,int y){

	if(y==0){
		return white;
	}else{
		real ratio = x
/y;
		return rgb(0.5*(1+ratio),0.7*(1+ratio),0.3*(1-ratio));
	}
}
unitsize(2,2);
 
picture damier;
// unitsize(damier,1,1);
size(damier,5000,5000,(-100,-100),(100,100));
 
dot(damier,(0,0));
dot(damier,(-num,-num),invisible);
dot(damier,(num,num),invisible);
 
 
 
for(int x=-num; x<=num;++x){	
 
	for(int y=-num; y<=num;++y){
 
		
		pen p=color_rational(x,y);
 
		if(y>0){
			pair far;
			if(isPrimeWith(abs(x),abs(y)) ){
				far=(x*100,y*100);
				drawline(damier,(0,0),far,p);
			}
		}

		if(y==0){
 
			dot(damier,(x,y));
			dot(damier,(x,y),rgb(0.9,0.9,0.9));

		}else
			dot(damier,(x,y),p);
 
	}
}

dot(damier,(0,0));
dot(damier,(0,0),rgb(0.9,0.9,0.9));
add(damier.fit(),(0,0));
// drawing the equivalent classes