SES is rewrite in light of Spectre security vulnerabilities which made Dr. SES like Proof-of-Work unsecure on common servers.
above / below
In this demo, the defender (above) has a secret "MacGuffin", in this case a random code which the attacker (below) is trying to guess. Everything is running inside a single SES RootRealm. The attacker's code (pasted into the text box) is evaluated by the defender when the Execute button is pressed. demo 
(demo source code )