My guests on this episode are the authors of Make Trigonometry, Build Your Way from Triangles to Analytic Geometry, Joan Horvath and Rich Cameron. Make Trigonometry is the third math book that Joan and Rich have written with us, the previous books being Make Geometry and Make Calculus. Joan calls herself a recovering rocket scientist. In that career, she worked on spacecraft headed to distant planents. Her co-author, Rich, has a very different background as an open source developer who has been involved in 3D printing since its emergence in the maker community.  Together they have come up with a way to teach math using 3D models that turn math into a hands-on learning experience for students.