No, the pentagon is not limited to only one thing. You can have as many inactive gems or knowledge chips there as you wish.
(I have never actually seen a situation where having more than one knowledge chip in the pentagon was a good idea, mind you.)
Remember of course that inactive gems do not give victory points or income.
(I have never actually seen a situation where having more than one knowledge chip in the pentagon was a good idea, mind you.)
Remember of course that inactive gems do not give victory points or income.