Inspired by this puzzle
Find the rule that each color chain on the left follows, but none on the right follow.
Raw text if you're colorblind or something (O = orange, Y = yellow, G = green, C = cyan):
COGGYCYOC GYGYG O YYGGGGYYY OC GYO GYYYGOG OCGCOYO CYOYOOY GCGCGCGC
CC GCYO YYYYYOOOO YCGOYCG OYCGCY GOC CCCGYOO OOY CYOGYYCG GOCOYOGGCO
If you want to see more cases, you may suggest up to 5 additional color chains, and I will sort them accordingly. As a rule of thumb, try to keep the length at $10$ blocks or less. You may suggest chains in this chat.
If you reverse a chain, it will stay on the same side.
If you recolor all green to be orange, everything will stay on the same side.
The rule can be described as the equality of two quantities.