Any FABRIK implementation advice/code?

[HLGgaming]

So I've been given the task of implementing a forward and backward reaching inverse kinematics algorithm onto just a simple set of connected shapes. So far its been going very bad, I've been looking at the work of Jeff Lander and his 'More Kine' project which is basically the same thing I am trying to achieve.

Unfortunately just by copying parts of the code over isn't enough and I get undeclared issues probably because the code is either really old or I'm just bad, either way can anybody link some FABRIK code or projects that are somewhat recent for me to study up on please?