#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define F first
#define S second
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

int main() {
	cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(cin.failbit);

	ll t;cin>>t;
	while(t--){
		ll n,m;cin>>n>>m;
		vi a(m);rep(i,0,m)cin>>a[i];

		ll l=0,r=n;
		while(l+1<r){
			ll mid=(l+r)/2;
			ll s=0;
			for(ll x:a){
				s+=max(0ll,x-mid);
			}
			if(s>mid*(n-mid))l=mid;
			else r=mid;
		}
		cout<<r<<"\n";

		char y[m][n];
		rep(i,0,m){
			rep(j,0,n){
				y[i][j]='.';
			}
		}
		vi c(r);
		rep(i,0,r)c[i]=n-r+i;
		rep(i,0,sz(c))cout<<c[i]<<" ";cout<<endl;
		rep(i,0,m){
			int z=min(r,(ll)a[i]);
			rep(j,0,z){
				y[i][c[j]]='#';
				a[i]--;
			}
			ll j=0;
			while(a[i]>0){
				if(c[j]==0||j>0&&y[i][c[j]-1]=='#'){
					j++;
				}else{
					c[j]--;
					y[i][c[j]]='#';
					a[i]--;
				}
			}
			
		}

		rep(i,0,n){
			rep(j,0,m)cout<<y[j][i];cout<<"\n";
		}
	}
}