Contact and tip info
Doug Sweetser email: firstname.lastname@example.org twitter: visualphysics
If it is really important to you, a google hangout can be arranged.
Quaternions.com, the mothership of my private research project.
Numbers 101, a visual introduction to space-time numbers, aka quaternions.
Measurement 101, a site dedicated to my new proposal for quaternion gravity
VisualPhysics.org has a collection of analytic animations generated with a user-hostile set of tools I wrote.
This is a part-time job for me that eats real money (~$60k over 2 decades).