It is easy to sketch the graph of

for

. For

,

is only defined for rational

with odd denominator,

*unless* complex values are allowed. In this case, set

, where log represents the principal branch of the complex logarithm; other branches differ by an integer multiple of

and these may be specified using the parameter

in the formula. Thus, any

value determines a 3D graph where each

value determines the point in space

. The collection of all of these graphs, or threads, forms the

spindle.