Curves and Approximations, by John R. Hendricks, privately published by the author, 1999. 36 pp., (stapled). ISBN 096847005x.
This short book contains some very interesting curves that are generally extensions of well known ones. The formulas used to create the curves are included as well as some BASIC code to plot them.
The cosine nodosus is a cosine curve that has a loop bisected by the y-axis in the middle and the binodal lemniscate is like a lemniscate but has an ovoid in the middle with a node on each end. The trinodal lemniscate has two loops in the middle with nodes on each end and the quadnodal lemniscate has three loops in the center.
Unusual curves have the additional property that they are interesting to look at. John R. Hendricks did a great deal of work in magic squares, cubes and tesseracts. In this book he adds some unusual and attractive curves to his extensive list of accomplishments.
Note: John R. Hendricks passed away in 2007, so this book may no longer be available.