🅰️1️⃣🅰️🅰️🅰️

#r1nxz #string structure #code format #letter number pattern #alphanumeric sequence

🪢#️⃣🪵

#rope net #cargo net #climbing net #hammock net #knotted mesh #string structure

『🅰️...🅰️』『🅱️...🅱️』

#anbn #a^n b^n #string structure #block pattern #formal grammar #concatenation