#include <iostream>#include <math.h>using namespace std;#define MAXM 110#define EPS 1e-8typedef struct{double x1,y1,x2,y2;}Segment;Segment segment[MAXM];int n;double distance(double x1,double y1,double x2,double y2){return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));}double corss(double x1,double y1,double x2,double y2,double x,double y){return (x2-x1)*(y-y1)-(x-x1)*(y2-y1);}bool judge(double x1,double y1,double x2,double y2){int i;if(distance(x1,y1,x2,y2)<EPS) return 0;for(i=0;i<n;i++){if(corss(x1,y1,x2,y2,segment[i].x1,segment[i].y1)*corss(x1,y1,x2,y2,segment[i].x2,segment[i].y2)>EPS) return 0;}return 1;}int main(){int t,i,j,ans;scanf("%d",&t);while(t--){scanf("%d",&n);for(i=0;i<n;i++)scanf("%lf%lf%lf%lf",&segment[i].x1,&segment[i].y1,&segment[i].x2,&segment[i].y2);if(n==1) {printf("Yes!n");continue;}ans=0;for(i=0;i<n && !ans;i++)for(j=i+1;j<n && !ans;j++){if(judge(segment[i].x1,segment[i].y1,segment[j].x1,segment[j].y1) ||judge(segment[i].x1,segment[i].y1,segment[j].x2,segment[j].y2) ||judge(segment[i].x2,segment[i].y2,segment[j].x1,segment[j].y1) ||judge(segment[i].x2,segment[i].y2,segment[j].x2,segment[j].y2))ans=1;}if(ans) printf("Yes!n");else printf("No!n");}return 0;}
