Optical Exact Ray Tracing

The attached Optical Exact Ray Tracing tutorial is published online: https://wp.optics.arizona.edu/optomech/wp-content/uploads/sites/53/2016/12/Tutorial_Ruiz_Maria.pdf

This tutorial is very helpful for plotting the location of the emerging ray vs. input ray height (fan plot) for a front spherical surface and a back planar surface. Would any one know how to modify this code to plot emerging ray vs. input ray height for a front spherical surface and a back SPHERICAL CONCAVE surface?

Thanks!