I came across the following drawing style while studying the subject of complex analysis for my qualifying exams. A cluster point is a point z about which an infinite sequence of isolated singular points of a single-valued function cluster, in such a way that there are an infinite number of isolated singular points in an arbitrarily small circle about z.
Intuitively, the closer you get to z, the more irregular the function is. The interesting thing is: though all the singular points get infinitesimally close (to each other, and to z), they are still isolated. I.e. there still exists a region around each point that contains no other singularities.
In the mathematical field of knot theory, a prime knot is a closed loop formed into a knot that is indecomposable (in short, cannot be rearranged into a simpler knot; this idea is analogous to prime numbers which are also indecomposable in a different sense). Prime knots on KnotGod's body are labeled by their Alexander-Briggs notation (n_k = kth element among all prime knots with n crossings).
I did try some tattooing, can't say I'm proud of them all, but this is my favorite.