An interesting card love dating game:
Target: Alice and Bob, if both love each other, dating; otherwise, not dating
Prerequisite:honest-but-curious, can’t be ‘malicious’
Method 1: ❤️: love ♣️: not love
Step 1: Alice went into the room, puts card face-down on table, ❤️ if love, ♣️ if no love Step 2: Alice leaves the room, Bob went into the room, if he loves Alice, open the card and get the result; otherwise, do nothing. Step 3: Bob return to tell Alice if they would date.
It is like ‘And’ function, only 1 will make an affect on the result. So if the person inputs 1, he/she should watch the other’s option; if the input is 0, then the result must be failure, so there is no need to watch the other’s choice and thus protecting the privacy of the other one that may have ❤️.
Method 2: 
Solution2
Secure 2-party computation
Alice and Bob want to learn some function on their joint inputs without disclosing their inputs, how to do it without cards? how to do it for any function?