Layers of income sources

These are the layers of income sources, similar to the cash flow quadrant. The four ways to make money.

Layer#:1  Employee.
Employees work for other people or companies money, be it skilled or unskilled. They must go to work, which means they exchange their time and effort to earn money if they don't go to work, they don't get paid.
An employee is one of the easiest sources of income because all it takes is just to apply and get the job if the economy is good. It sometimes comes with a benefit like medical and pension.
On the other hands, an employee is limited or saturated income source because money can only be made within a twenty four hours period and most employee works an average of eight hours a day.
There isn't any leverage as an employee, which means money or investment can not be working for them, they have to physically do the work to get paid.
The tax bracket or implication of an employee is also high as compared to business owners or investors ranging from 15 - 30% because the employee is a liability to the government in case their lose their job or critical illness the government. 

Layer#:2  Self-Employed.
Self-Employed work for themselves, they are their bosses. They have educated themselves to exchange their knowledge and expertise for money by providing services, examples are an Accountant owning a tax service firm, or a medical doctor owning a  small medical clinic.
Self-employed make the decision what time to go to work, their benefit and when to take a vacation.
The tax implication of self-employed is fair and moderate as compared to the employee because they reduce the unemployment rate by creating one to two employment.
Self employed is also limited and saturated source of income similar to an employee. In some cases there is no leverage because they also have to be present to perform the job before getting paid.

Layer#:3  Big Businesses.
These are businesses with over five hundred employees. The owners have people working for them while the enjoy their leisure. Most big business are owner by investment groups or partnership like Google, Walmart.
Big business income is unlimited and unsaturated because they can have people working for them all over the work, twenty four hours a day.
There is complete leverage because other people work and make money for the owners.
The taxes of big business are low because they create employment to the population which means they are helping the government to reduce the unemployment rate. In some cases the government even subsidize big businesses.

Layer#:4  Investors.
Investors are people who have money working for them, entrepreneurs and business experts. They invest their money in ventures like real estate, the stock market, and businesses.
Investors make passive income, which is making money with little or no effort.
Their income is unlimited and unsaturated since they make money all round the year with their investment, not limited to a couple of hours a day. 
There is complete leverage because money is working for them twenty-four hours a day also.
The tax bracket of investors is also low as compared to employees and self-employed. It sometimes depends on how long the money is invested.

In conclusion, it might be difficult to move from one layer to another. According to Robert Kiyosaki's book, Rich Dad Poor Dad  this can be achieved by financial education.
Moving from self-employed to business obviously requires some skills which can be acquired by reading books like, How to Start a Business: Step-By-Step and Starting a Business: All-In-one For Dummies
Getting into layer #4. Investors equally can be acquired by reading books like, The Little Book of Common Sense Investing and The Single Best Investment