TMNT improved articulated flex joint

This is slight modification for Dragon Mountain's Design TMNT Action Figures. Original solution needs to use FLEX material for joints. With some modifications inspired by comment/make of w2media and together my own modification, I was able to finish model with only using PLA and some (brute) force and sometimes hammer :D  

This is articulated joint modified to shape that can be made from other materials then FLEX (e.g. PLA). With this modification it is possible to assemble original model fully from PLA.