I am working on building an interactive mathematics book exploring various curves and their properties/applications.

Two wonderful books which initiated me into this topic are

https://archive.org/details/lml-remarkable-curves https://archive.org/details/StraightLinesAndCurves

I learnt a lot from these, and found other books which are detailed explorations. Using interactive applets would make wonderful companions for these explorations.

I am planning to use jsxgraph for the interactive applets.