How do i put colour into this program help please

[bids]

#include <conio.h>
#include <graphics.h>
#include <math.h>
#include <stdlib.h>
#include <dos.h>
void serp(int level, int Ax, int Ay, int Bx, int By)
{
	int poly[4]={Ax,Ay,Bx,By};

	setfillstyle(SOLID_FILL,YELLOW); not working the way i want.

	if (level>0)
	{

		serp(level-1, Ax,Ay ,(2*Ax+Bx)/3,(2*Ay+By)/3);
		serp(level-1,(2*Ax+Bx)/3,(2*Ay+By)/3,(Ax+Bx)/2+sqrt(3)*(Ay-By)/6,(Ay+By)/2+sqrt(3)*(Bx-Ax)/6);
		serp(level-1,(Ax+Bx)/2+sqrt(3)*(Ay-By)/6,(Ay+By)/2+sqrt(3)*(Bx-Ax)/6,(Ax+2*Bx)/3,(Ay+2*By)/3);
		serp(level-1,(Ax+2*Bx)/3,(Ay+2*By)/3,Bx,By);
        }
	else fillpoly(2,poly);
}

int main(void)
{
	int graphdriver=DETECT, graphmode;
	initgraph(&graphdriver, &graphmode, "");

	int i, N=8, Bx=0, By=235, Ax=635, Ay=235;

	for (i=0; i<N; i++)
	{

	serp(0,Ax,Ay,Bx,By);

	serp(1,Ax,Ay,Bx,By);
	serp(2,Ax,Ay,Bx,By);
	serp(3,Ax,Ay,Bx,By);
	serp(4,Ax,Ay,Bx,By);
	serp(5,Ax,Ay,Bx,By);
	serp(6,Ax,Ay,Bx,By);
	serp(7,Ax,Ay,Bx,By);

	delay(1000);
	cleardevice();
	}

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

i want to make other other shapes in different colours