Not the busiest of years, but I at least found a few little curiosities to amuse myself with, and made a little progress on some serious mathematics.
Wrote up a heinous hack I'd used to code round a problem; thankfully, it's since been retired.
A neat little result about how many times each prime shows up as a factor in the product of all the positive naturals up to a given one.
A neat little result about how much is left when you cut out a cylindrical core from a sphere.
Made my implementation of Conway's cellular automaton a little easier to play with.
Separated power from polynomial and began generalising it.
Explored the gradients of chords to show how an algebraically formulated deriviative matches my latest reformulation of how to do differentiation. Explored several other details (e.g. multinomials, particularly homogenous ones) in support of that.
Began describing one of the tools that shows up repeatedly all over mathematics.