This is Day 9 of my collection of printable equations. To see the whole collection, go to:http://www.thingiverse.com/thing:227210
For today's equation, we have the final in the series of equations of the form |x^b + y^c| = a (See days 2, 6, 7, and 8). Previously, we saw that as b and c went from <1, to 1, to >1, to 2, the quadrants of the shape went from bending inward, to straight, to bowing out, to a circle. As b,c --> infinity, the quadrants continue to extend out until they form a square. Today's equation: x^20 + y^20 = a, is a close approximation of that, though you can still see some rounding at the corners. You can see the progression in the posted photo.
As always, I'm going to continue to post one equation per day until get bored or people lose interest. If there's a particular equation you'd like to see, leave a comment and I'll give it a shot.