QG-L5: 2nd QG-Quasi Euler line The 2nd QG-Quasi Euler line is the line through QG-P8 (2nd Quasi Centroid), QG-P9 (2nd Quasi Circumcenter), QG-P10 (2nd Quasi Orthocenter) and QG-P11 (2nd Quasi Nine-point Center). Coefficients: The coefficients of QG-L5 can be easily derived by calculating the Crossdifference (see Ref-13, keyword: crossdifference) of QG-P8 and QG-P9. Properties: QG-L5 is the Euler line of the 2nd QG-Quasi Diagonal Triangle QG-Tr2. The 2nd QG-Quasi Euler line QG-L4 // the 1st QG-Quasi Euler line QG-L5. QG-P1 is the Railway Watcher (see QA-L-1) by the 1st QG-Quasi Euler line QG-L4 and the 2nd QG-Quasi Euler line QG-L5 (note Eckart Schmidt).