How does progressive income tax work?

Concept, POOR pay none or very little and the rich pay a bunch.

In law, The system is that the Poor pay very little and as your personal income increases your tax bill increases in step. At a certain point the increases stop and you are billed at the maximum rate. In Ontario Canada the maximum rate is targeted to be 50%

How it actually works is the Middle Class, 70% of the population pay 50% and the very rich and very poor pay much less.