/**
 *  Special thanks to Paul Heckbert
 *
 *  http://tproger.ru/translations/business-card-raytracer
 */

#include <stdlib.h>   
#include <stdio.h>
#include <math.h>

#define WIDTH  512
#define HEIGHT 512

struct Vector {

	Vector() {
	}

	Vector(double a, double b, double c) {
		x = a;
		y = b;
		z = c;
	}

	double x, y, z;

	Vector operator+(Vector r) {
		return Vector(x + r.x, y + r.y, z + r.z);
	}

	Vector operator*(double r) {
		return Vector(x * r, y * r, z * r);
	}

	double operator%(Vector r) {
		return x * r.x + y * r.y + z * r.z;
	}

	Vector operator^(Vector r) {
		return Vector(y * r.z - z * r.y, z * r.x - x * r.z, x * r.y - y * r.x);
	}
	
	Vector operator!() {
		return *this * (1 / sqrt(*this % *this));
	}
};

int G[] = { 
	0x0003C712,  // 00111100011100010010 
	0x00044814,  // 01000100100000010100
	0x00044818,  // 01000100100000011000
	0x0003CF94,  // 00111100111110010100
	0x00004892,  // 00000100100010010010
	0x00004891,  // 00000100100010010001
	0x00038710,  // 00111000011100010000
	0x00000010,  // 00000000000000010000
	0x00000010,  // 00000000000000010000
};

double Random() {
	return (double) rand() / RAND_MAX;
}

int tracer(Vector o, Vector d, double &t, Vector& n) {
	t = 1e9;
	int m = 0;
	double p = -o.z / d.z;
	if (.01 < p){
		t = p;
		n = Vector(0, 0, 1);
		m = 1;
	}
	for (int k = 19; k--;)
		for (int j = 9; j--;)
			if (G[j] & 1 << k) {
				Vector p = o + Vector(-k, 0, -j - 4);
				double b = p % d; 
                                double c = p % p - 1; 
                                double q = b * b - c;
				if (q > 0) {
					double s = -b - sqrt(q);
					if (s < t && s > .01) {
						t = s; 
						n = !(p + d * t);
						m = 2;
					}
				}
			}
	return m;
}

Vector sampler(Vector o, Vector d) {
	double t;
	Vector n;
	int m = tracer(o, d, t, n);
	if (!m){
		return Vector(.7, .6, 1) * pow(1 - d.z, 4);
	}
	Vector h = o + d * t;
        Vector l = !(Vector(9 + Random(), 9 + Random(), 16) + h * -1);
        Vector r = d + n * (n % d * -2);
	double b = l % n;
	if (b < 0 || tracer(h, l, t, n)){
		b = 0;
	}
	double p = pow(l % r * (b > 0), 99);
	if (m & 1) {
		h = h * .2;
		return ((int) (ceil(h.x) + ceil(h.y)) & 1 ? Vector(3, 1, 1) : Vector(3, 3, 3)) * (b * .2 + .1);
	}
	return Vector(p, p, p) + sampler(h, r) * .5;
}

int main(int argc,char **argv) {
	printf("P6 %d %d 255 ",WIDTH,HEIGHT);
	Vector g = !Vector(-6, -16, 0);
        Vector a = !(Vector(0, 0, 1) ^ g) * .002; 
        Vector b = !(g ^ a) * .002;
        Vector c = (a + b) * -256 + g;
	for (int y = HEIGHT; y--;) {
		for (int x = WIDTH; x--;) {
			Vector p(13, 13, 13);
			for (int r = 64; r--;) {
				Vector t = a * (Random() - .5) * 99 + b * (Random() - .5) * 99;
				p = sampler(Vector(17, 16, 8) + t, !(t * -1 + (a * (Random() + x) + b * (y + Random()) + c) * 16)) * 3.5 + p;
			}
			printf("%c%c%c", (int) p.x, (int) p.y, (int) p.z);
		}
	}
}