As a follow-up to the question Are there any good computer programs for drawing (algebraic) curves?, are there any programs that can plot real algebraic curves in (a model of) the projective plane?
Here are a few curves on the real projective plane. https://dl.dropboxusercontent.com/u/68698001/projplot/index.html
This is the Klein quartic. The red line is the x-axis, the green line is the y-axis, and the blue line is the line at infinity.