You can play too at https://supertestnet.github.io/statechainjs/

And you can use the operator that is running (temporarily) on a tab in my browser: nprofile1qyghwumn8ghj7mn0wd68yat99e3k7mgqypra76pf57wehys7f282dql7xm3cl97m3s45ygmts953n0dnujp7w5ncm7x