When cycling through instances it often occurs that we land on an instance that has already been visited. This is a problem because it is very likely that the instance was not working (otherwise we would have stopped there).

My proposal is to improve randomness by temporarily removing instances that have already been visited:

1. [X, Y, Z, H, T]: H has been chosen, let's remove it so if the user doesn't like it, he's not likely to return to it
2. [X, Y, Z, T]: Z has been chosen, let's remove it so if the user doesn't like it, he's not likely to return to it
3. [Y, Z, T]: X has been chosen, let's remove it so if the user doesn't like it, he's not likely to return to it
4. ...
5. []
6. [X, Y, Z, H, T]
7. ...

At each iteration, instances already visited by the user are removed. When the array of instances becomes empty, it is repopulated and we start over.