// rotating pyramid

#include<graphics.h>
#include<conio.h>
#include<dos.h>
#include<math.h>

# define pi 3.141592736

float cosa,cosb,sina,sinb;
void ini(float cos1,float cos2)
{
 cosa=cos(cos1*pi/180);
 cosb=cos(cos2*pi/180);
 sina=sin(cos1*pi/180);
 sinb=sin(cos2*pi/180);
}
void plot(int x,int y,int z,int &x1,int &y1)
{
 x1=x*cosa-y*sina;
 y1=x*sina*sinb+y*cosa*sinb+z*cosb;
 x1=320+int(x1);
 y1=240-int(y1);
}
void main()
{
 int gd=DETECT,gm;
 initgraph(&gd,&gm,"c:\\tc\\bgi");
 int p=0;
 while(!kbhit())
 {
 ini(p,p);
 int x[5],y[5];
 plot(5,5,1,x[0],y[0]);
 plot(45,5,1,x[1],y[1]);
 plot(5,45,1,x[3],y[3]);
 plot(45,45,1,x[4],y[4]);
 setcolor(RED);
 line(x[3],y[3],x[4],y[4]);
 line(x[1],y[1],x[4],y[4]);
 line(x[0],y[0],x[3],y[3]);
 line(x[0],y[0],x[1],y[1]);

 plot(25,25,140,x[2],y[2]);

 for(int i=0;i<5;i++)
  {
  setcolor(BROWN);
  line(x[2],y[2],x[i],y[i]);
  }
 p+=3;
 delay(20);
 cleardevice();
 }
}