Every non-zero complex number has precisely two square roots in a plus/minus pair. To get a continuous square root function, we may slit the plane by removing the negative real axis. The resulting square root that is positive along the positive real axis is the "principal branch" of square root, whose image is light green. The other branch, obtained by rotating the image a half-turn about 0, fits neatly together.
Printed on high-quality 170 gsm poster paper with a satin finish.
