" •Businesses that do not require my presence I own them, but they are managed or run by other people. If I have to work there, it’s not a business. It becomes my job. •Stocks •Bonds •Income-generating real estate •Notes (IOUs) •Royalties from intellectual property such as music, scripts, and patents •Anything else that has value, produces income or appreciates, and has a ready market "
― Robert T. Kiyosaki , Rich Dad, Poor Dad