• Math and the Art of M.C. Escher online textbook.
• SLU Math Team: Training material and history.
• PREP 08 Geometry & Art Workshop - workshop for mathematics educators I ran in June 2008 with Anneke Bart.
• Symmetry at the Cathedral - a page dedicated to symmetry groups found at the Cathedral Basilica of St. Louis.

• Math 120 "College Algebra"
  
• Math 130 "Elementary Statistics with Computers"
• Math 132 "Survey of Calculus"
• Math 142 "Calculus I"
• Math 143 "Calculus II"
• Math 266: Principles of Mathematics
• Math 355 "Differential Equations"
• Math 370 "Advanced Math For Engineers"
• Math 403: "Probability and Statistics for Engineers"
• Math 451: Complex Analysis I
• Math 452: Complex Analysis II
• CS 150: Object Oriented Programming
• CS 220 "Computer Science II"
• EE/CS 305 "Microprocessors"
• CS 324 "Operating Systems"
• CSCI 357: Computer Graphics
• Math 110-111 (U. of Chicago, 1995-6).

Strange Horizons is an online magazine of speculative fiction. I wrote a series of general interest mathematics articles which appeared in the magazine.

• The Fourth Dimension (Sep. 2002)
  (or, try the Portugese translation. Thanks, Marcelo!)
• Folding (Mar. 2002)
• Steganography: How to Send a Secret Message (Oct. 2001)
• The Biggest Numbers in the Universe (Apr. 2001)
• Habitrails and Asteroids: Topology From the Inside (Jan. 2001)