a
  three-dimensional convex polytope with marked points

Notes and papers

An extended (and unfinished) tutorial on creating pictures using the software Asymptote.

A surprisingly strong relative version of the algebraic Hartogs' lemma. [not intended for publication]

Math 130's (Elementary Functions and Calculus) notes:
Math 131 (Autumn 2011, Autumn 2012),
Math 132 (Winter 2012),
Math 133 (Spring 2012)

These notes sketch a definition for Cartier divisors in terms of rational sections rather than local data. The only source I know for this is EGA. They were originally written for a seminar on Fulton's Intersection Theory assuming knowledge of Ravi Vakil's notes on algebraic geometry.

An elementary proof of generic freeness.

The (weak) Lefschetz principle via model theory.

Notes on connectedness: first lecture, second lecture

Second half of refresher talk on point-set topology for incoming first-year graduate students (September 2010)

My undergraduate thesis on tropical geometry, completed under the supervision of Eric Katz.