C graphics circle movement

Hey guys I need help in C programming
Im trying to make program with a circle inside few tiny circle move from one end to other
I have created circle and tiny circles(particles) but they move in same order I want it as follows
1.> First particle moves , and when it returns the next moves and so on
2.> First particle moves while returning second moves same for third

pls refer the following code:

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

int main() {
 int gd = DETECT, gm;
 int i, x, y,x1,y1 ,flag=0;
 initgraph(&gd, &gm, "C:\\TC\\BGI");

 /* get mid positions in x and y-axis */
 x = 180;//getmaxx()/2;
 y = getmaxy()/2;
 x1= getmaxx()/2;
 y1=getmaxy()/2;

 while (!kbhit()) {
  setcolor(GREEN);
 circle(x1-160,y1,150);
 if(x >= getmaxx()-240 ||x <=175)
     flag = !flag;
    setcolor(BLUE);
    setfillstyle(SOLID_FILL,BLUE);
    circle(x-160,y,5);
    floodfill(x-160,y,BLUE);
       setcolor(RED);
    setfillstyle(SOLID_FILL,RED);
    circle(x-140,y+20,5);
    floodfill(x-140,y+20,RED);
       setcolor(YELLOW);
    setfillstyle(SOLID_FILL,YELLOW);
    circle(x-120,y-20,5);
    floodfill(x-120,y-20,YELLOW);



 /* delay for 50 milli seconds */
 setcolor(10);

 delay(10);

 /* clears screen */
 cleardevice();
 if(flag){
 x=x-1;

 } else {

    x=x+1;
 }
    }

    getch();
    closegraph();
    return 0;
}

////

Ill repeat

I want
1.> Yellow to move to end of circle and come back then Red should move same to blue ....
2.> Yellow to move to end of circle then Red should move while yellow is coming back and once yellow is back Blue shud move

Hope I have made my point clear
Thank you for reading