I was thinking of building something but I first must know a little bit more about magnets. First of all where could I buy good magnets of all sorts, with different strengths. Are there any stores like home hardware or renodepot that are known for selling magnets? Would they sell very strong magnets to anyone? And how strong are the strongest magnets? Another thing is say I bought a normal rectangular magnet. Would it have a negative and positive side or are some magnets positive and some negative. Hahaha I know this is a stupid question but I am just making sure I always thought that every magnet has a north and south + and -. Lastly I want to know if I put a metal cube in the middle of stationary magnets one being very strong and the other being somewhat weak would the metal only be attracted to the strong one or would it also be attracted to the weak one?