Let's hope you're not allergic to flying insects, cuz this one is sure to cause a reaction! This 4 suited spider solitaire is the hardest version on the site. Played with 4 suits, you're going to have to stack / recombine cards of various colors on top of one another to wind up reaching your objective: build 4 stacks of cards, from king-to-ace. As each stack is built, it will disappear from the board--giving you more room to move your cards.