Thread: Sierpinski Triangle bug

I'm trying to make a Sierpinski Triangle using recursion and StdDraw, but I can't figure out how to make it work correctly. I know how to draw the triangles in the correct spots, but I can't make the recursion work in a way that it can draw the multiple triangles in one loop of the recursion. What I need to figure out is how to make that pattern in every subsequent triangle that is drawn as a result of the recursion.

public class Triangle
{
    public static void drawTri(double x, double y, double s) {
        if (s<5 ) { return; }
        else {
            double[] a = {x,x+s/2,x+s};
            double[] b = {y,y+s*Math.sqrt(3)/2,y};
            StdDraw.polygon(a,b);
            double[] c = {x,x+s/4,x+s/2};
            double[] d = {y,y+s*Math.sqrt(3)/4,y};
            double[] e = {x+s/2,x+3*s/4,x+s};
            double[] f = {y,y+s*Math.sqrt(3)/4,y};
            double[] g = {x+s/4,x+s/2,x+3*s/4};
            double[] h = {y+s*Math.sqrt(3)/4,y+s*Math.sqrt(3)/2,y+s*Math.sqrt(3)/4};
            StdDraw.polygon(c,d);
            StdDraw.polygon(e,f);
            StdDraw.polygon(g,h);
            drawTri(x,y,s/2);
        }
    }
 
    public static void main(int size) {
        StdDraw.setXscale(0, size);
        StdDraw.setYscale(0, size);
        StdDraw.setPenColor(StdDraw.BLUE);
        drawTri(0, 0, size);
    }
}