<zgrep> misle/rn @/|a+b@| = { \xe2\x88\x9a(a\xc2\xb2-b\xc2\xb2) if a\xc2\xb2-b\xc2\xb2 \xe2\x89\xa5 0 ; i\xe2\x88\x9a(a\xc2\xb2-b\xc2\xb2) if a\xc2\xb2-b\xc2\xb2 < 0 }

Precession is the opposite of succession. It is the joy of children and the curse of first year physics students.