A one-time pad is known to be theoritcally secure, nothing can break it. However, if the key is reused, the one time pad becomes theoritically breakable.
But even RSA is theorically breakable yet it's widely used because it's practically secure. So, is a One-Time pad with a sufficiently long looping key practically secure?
If it's secure, how long does the key need to be in order for it to become practically unbreakable on a modern PC?
If it's insecure, why? how does one break it?
An example of a looping OTP Key: