A few years ago, there was another site somewhere that posted a similar cut-away of that lens... which is on display at some Leica place. Its amazingly complex and neat to look at that cut away.
Several years ago, I had that exact lens which was my 1 and only street shooter. Worked well even though it was slow at a max aperture of f/4. Well guess what? I dropped it and knocked the aperture ring off whack! Leica NJ, basically said no way! They didn't have a technician that was familiar enough with the most complex lens in the Leica M line. I contacted Leica Solms-Germany and they quoted me over $500USD just to start looking into it.. EEK! Fortunately, a friend of mine pointed me to a hole-in-the-wall place in Jersey that had an older Chinese fellow fix it for me... final cost... $135.
Sold it for $800 more than I had invested a few years later. Its a sweet lens to have.. too bad Leica stopped making it. In a way, I regret not keeping it but it didn't see much use after I started to pick up other more "traditional" leica lenses.
Oh... I didn't notice they had the Summilux 50mm ASPH cut away on there too. neat... I've never seen that one. Its $3700USD and probably one of the most difficult to locate new. I wanna see a Noctilux cut away.