I’d suggest the general solution: the machine can keep a list of the songs it has played, and bump the oldest entries off the list. The list length can be user

I’d suggest the general solution: the machine can keep a list of the songs it has played, and bump the oldest entries off the list. The list length can be user configurable, 0 handles your truly random friend, 1 would be enough to just avoid immediate repeats, or it could be set to the size of the library. 100 could, I think, give you enough time to not notice any repeats I think, right?