/* Code by pp_orange */
//#pragma GCC optimize(2)
#include<bits/stdc++.h>
#define m_p(a,b) make_pair(a,b)
#define pb push_back
#define ll long long
#define ull unsigned long long
#define ld long double
#define inf 0x7FFFFFFF
#define inff 9223372036854775807
#define rep(i,l,r) for(int i=l;i<r;++i)
#define repp(i,l,r) for(int i=l;i<=r;++i)
#define per(i,r,l) for(int i=r-1;i>=l;--i)
#define pper(i,r,l) for(int i=r;i>=l;--i)
#define pii pair<int,int>
#define fi first
#define se second
#define p_q priority_queue
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define ls(x) ((x)<<1)
#define rs(x) ((x)<<1|1)
#define lb(x) ((x)&-(x))
#define lg(x) (31^__builtin_clz(x))
#define vi vector<int>
#define vii vector<pii >
const int mod = 998244353;
//#define int ll
const int intsz = sizeof(int);
using namespace std;
inline int rd(){
	int x(0),f(1);char ch=getchar();
	while(!isdigit(ch)){if(ch=='-')f=-f;ch=getchar();}
	while (isdigit(ch)){x=(x<<3)+(x<<1)+(ch^48);ch=getchar();}
	return x*f;
}
inline void out(int X){
	if(X<0) {X=~(X-1); putchar('-');}
	if(X>9) out(X/10);
	putchar(X%10+'0');
}
ll pw(ll x,int d){
	ll t = 1;
	for(;d;d>>=1,x=x*x%mod)if(d&1)t = t*x%mod;
	return t;
}
#define MAX 100005
set<pii> st;
int lim[MAX][26];
int lgt[MAX];
int lstlim[26];
int yg[MAX];
char ansc[5000005];
int cmp(int x,int y){
	bool flag1 = 1,flag2 = 1;
	rep(i,0,26){
		flag1 &= (lim[x][i]<=lim[y][i]);
		flag2 &= (lim[x][i]==lim[y][i]);
	}
	if(flag2)return -1;
	return flag1;
}
bool ins(int idx){
	auto it = st.insert({lgt[idx],idx}).fi;
	int tmp;
	// cout<<"here\n";
	if(it!=st.begin()){
		tmp = cmp(prev(it)->se,idx);
		if(tmp==-1){
			st.erase(prev(it));
		}else if(tmp==0){
			return 0;
		}
	}
	if(next(it)!=st.end()){
		tmp = cmp(idx,next(it)->se);
		if(tmp==-1){
			st.erase(next(it));
		}else if(tmp==0){
			return 0;
		}
	}
	return 1;
}
signed main(){
	//freopen("in.in","r",stdin);
	//freopen("out.out","w",stdout);
	int T = rd();
	string s;
	while(T--){
		st.clear();
		int n = rd();
		repp(i,1,n){
			cin>>s;
			rep(j,0,26)lim[i][j] = 0;
			lgt[i] = s.length();
			yg[i] = lgt[i];
			rep(j,0,lgt[i]){
				lim[i][s[j]-'a']++;
			}
		}
		bool flag = 1;
		pper(i,n,1){
			while(st.begin()!=st.end()){
				auto it = prev(st.end());
				if(it->fi<lgt[i])break;
				int idx = it->se;
				int t = lgt[idx]/lgt[i];
				lgt[idx] %= lgt[i];
				rep(j,0,26){
					lim[idx][j] -= lim[i][j]*t;
					if(lim[idx][j]<0){
						flag = 0;
						break;
					}
				}
				if(!flag)break;
				st.erase(it);
				if(lgt[idx]){
					flag = ins(idx);
					if(!flag)break;
				}
			}
			if(!flag)break;
			flag = ins(i);
			if(!flag)break;

			// cout<<"i = "<<i<<endl;
			// for(auto [x,y] : st){
			// 	cout<<x<<' '<<y<<endl;
			// }
		}
		if(!flag){
			cout<<"NO\n";
		}else{
			cout<<"YES\n";
			rep(i,0,26)lstlim[i] = 0;
			int cnt = 0;
			for(auto [xxxxxx,y]:st){
				rep(i,0,26){
					rep(j,lstlim[i],lim[y][i]){
						ansc[cnt++] = (char)('a'+i);
						cout<<(char)('a'+i);
					}
					lstlim[i] = lim[y][i];
				}
			}cout<<endl;
			repp(i,2,n){
				rep(j,0,yg[i]){
					ansc[j] = ansc[j%yg[i-1]];
					cout<<ansc[j];
				}
				cout<<endl;
			}
		}

	}
	return 0;
}