This is the example where you're taxing 100%, my scenario is much more friendly, but as you can see the curve is pretty identical, only more accentuated. Also, notice that I zoomed out 4x, so you can see that even earning obscene ammounts, with 100% tax, you'll never manage to get more than three times the legal monthly minimum wage.
IRS 2012 in Portugal: how many € people earn monthly vs. how much they get (after taxes collection)
Grab the code here. The presentation was inspired by one of Raphaël's demos...