Turing Tumble Community

Challenge 37 problem

Hi Guys,
First of all, I am not a beta kind of person so I apologize for my question ;-).
This is my outcome on 7+9 in challenge 37. I thought register B would indicate 15 and then put one marble in the overflow bin. But apparently I’m doing something wrong or making a logical fallacy. Can someone help me out? Thanks in advance!20211231_095400

Got it now: it “resets” itself after reaching 15. Saw it in this YT video:


After 4m12sec.