Q$\mathrm{.}3$ Project Managers X$,$ Y$,$ Z of the various different companies but part of the Same Organization was attending an offshore Project Management summit. During that Summit each one of them were presenting Case studies which they are currently use and the success stories

$($a$)$ X$-$Project manager$$s case study is more about a project method that has reduced inefficiencies, visual approach and team member is clear about workflow and progress all the time. Please identify what project model is being used and explain in detail with example.

$($b$)$ Y$-$Project manager$$s case study is more about a project method wherein the motto is value stream impacting positively by eliminating waste from key processes and optimization of verticals, technologies and domain assets, please identify what project model is being used and explain in detail with example.