void sierpTriangles(int x1,int y1,int x2,int y2,int x3,int y3){
if(x1+3>=x2) return; //check for base case
//if the above case is not met, draw another triangle
int xleft=(x1+x3)/2,xright=(x2+x3)/2,xtop=(x1+x2)/2; //drawing step
int ymiddle=(y1+y3)/2,ytop=y1;
gfx_triangle(x1,y1,xtop,ytop,xleft,ymiddle);
gfx_triangle(xtop,ytop,x2,y2,xright,ymiddle);
gfx_triangle(xleft,ymiddle,xright,ymiddle,x3,y3);
//3 total recursive steps
sierpTriangles(x1,y1,xtop,ytop,xleft,ymiddle);//top left triangle
sierpTriangles(xtop,ytop,x2,y2,xright,ymiddle);//top right triangle
sierpTriangles(xleft,ymiddle,xright,ymiddle,x3,y3);//bottom middle triangle
}
int drawturtle(int x, int row, int wseg, int hseg, int boardw, int boardh, int col, int board[][col])
{
int xb,yc=boardh*row+4*hseg,hr=10,tr=5,i,it; //define parameters
xb=x/boardw;
if(xb<col && xb>=0)
board[row][xb]=1; //update position of turtle on board
if(xb+1<col && xb+1>=0)
board[row][xb+1]=0; //reset previous position of turtle on board
gfx_color(50,25,0); //dark brown color
for(i=0; i<wseg; i++) //draws shell
gfx_ellipse(x,yc,i,i);
gfx_color(20,150,0); //green color
for(i=0; i<hr; i++) //draws head
gfx_ellipse(x-wseg,yc,i,i);
for(i=tr; i>0; i--) //draws tail
gfx_triangle(x+wseg,yc+i,x+wseg,yc-i,x+wseg+i,yc);
if(x<0) //if turtle goes off board
x=width; //reset position of turtle
else
x--; //decrement x to move left
return x; //return new position of turtle
} //end drawturtle
