E4 (Empty Erlenmeyer Experiment Expansion) is the first official expansion for Experiment. This expansion gives the players new options to choose and new strategies to play the game. E4 introduces a new card type: the special lab card. Special lab cards are mysterious, no player may look at them before taking them. You never know what you are going to get ... it might be a double colour joker but it can also be a normal one colour flask or even an empty Erlenmeyer. The card remains hidden for your opponents so they won't know what you have until you use it. An empty Erlenmeyer can even give you in certain situations the edge of winning a close game with half a point. E4 also adds 6 new secret lab cards for even more fun.