#include "library.h"  

const double pi = acos(-1.0);
const double ninety = pi/2, degrees = pi/180;

bool block2(double p1x, double p1y, double p2x, double p2y, 
            double len, double beta, double end)
{ const double base = sqrt((p1x-p2x)*(p1x-p2x) + (p1y-p2y)*(p1y-p2y));
  const double alpha = atan2(p2x-p1x, p1y-p2y) - ninety;
  if (sin(beta) > 2*len/base)
    return false;
  const double p3x = (p1x + p2x) * 0.5;
  const double p3y = (p1y + p2y) * 0.5;
  const double p4x = p3x + len * sin(alpha+beta);
  const double p4y = p3y - len * cos(alpha+beta);
  const double dx = 0.5 * end * sin(ninety-alpha-beta);
  const double dy = 0.5 * end * cos(ninety-alpha-beta);
  const double p5x = p4x - dx;
  const double p5y = p4y - dy;
  const double p6x = p4x + dx;
  const double p6y = p4y + dy;
  move_to(p1x, p1y);
  draw_to(p2x, p2y);
  draw_to(p6x, p6y);
  if (len<3)
    draw_to(p5x, p5y);
  else
  { block2(p5x, p5y, p6x, p6y, len*.66, random_in_range(-40, 40)*pi/180, end*.66);
    block2(p5x, p5y, p6x, p6y, len*.66, random_in_range(-40, 40)*pi/180, end*.66); }
  draw_to(p1x, p1y);
  return true; }

void main()
{ make_window(1000, 800);
  block2(250, 780, 450, 780, 200, 0, 100); }