#include<cstdio>
int q,n,i,j,xmax,xmin,ymax,ymin,a,b,c,d,ax,ay,bx,by,cx,cy,dx,dy,ok,v[3][110];
int det(int ax,int ay,int bx,int by,int cx,int cy){
    return (ax-cx)*(by-cy) - (ay-cy)*(bx-cx);
}
int main(){
    scanf("%d",&q);
    for(i=1;i<=q;i++){
        scanf("%d",&n);
        xmax = -1000000;
        xmin = 1000000;
        ymax = -1000000;
        ymin = 1000000;
        for(j=1;j<=n;j++){
            scanf("%d%d",&v[0][j],&v[1][j]);
            if( v[0][j] < xmin )
                xmin = v[0][j];
            if( v[0][j] > xmax )
                xmax = v[0][j];
            if( v[1][j] < ymin )
                ymin = v[1][j];
            if( v[1][j] > ymax )
                ymax = v[1][j];
        }
        ax = xmin;
        ay = ymin;
        bx = xmin;
        by = ymax;
        cx = xmax;
        cy = ymax;
        dx = xmax;
        dy = ymin;
        ok = 1;
        for(j=1;j<=n;j++){
            a = det( ax,ay,bx,by,v[0][j],v[1][j] );
            b = det(bx,by,cx,cy,v[0][j],v[1][j]);
            c = det(cx,cy,dx,dy,v[0][j],v[1][j]);
            d = det(dx,dy,ax,ay,v[0][j],v[1][j]);
            if( a != 0 && b != 0 && c != 0 && d != 0 ){
                ok = 0;
                break;
            }
        }
        if(!ok)
            printf("NO\n");
        else
            printf("YES\n");
    }



    return 0;
}