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.
Handmade in the UK by specialist picture framers using premium fine art paper with a gently textured surface and satin finish, high-quality wood, and an FSC certified off-white mat. Delivered ready for hanging.
