#include<cstdio>#include<algorithm>using namespace std;const int num=10005;struct node{int x,y;}data[num];bool cmp(const node &a,const node &b){if(a.x!=b.x)return a.x<b.x;return a.y<b.y;}int main(){int t,n,i,flag;double sx,sy,ex,ey;//freopen("in.txt","r",stdin);scanf("%d",&t);while(t--){scanf("%d",&n);for(i=0;i<n;i++)scanf("%d%d",&data[i].x,&data[i].y);sort(data,data+n,cmp);sx=(double)data[0].x+(double)data[n-1].x;sy=(double)data[0].y+(double)data[n-1].y;flag=1;for(i=1;i<=n/2;i++){ex=(double)data[i].x+(double)data[n-1-i].x;ey=(double)data[i].y+(double)data[n-1-i].y;if(ex!=sx||ey!=sy){flag=0;break;}}if(flag==1)printf("yesn");elseprintf("non");}return 0;}
