Picture this: You slide a RM1 note into a parking machine, but then - whoosh! - the machine spits it out. You try and try again, only to have the machine reject it over and over again. ARGH, WHY?
A now-viral tweet may just hold the answer to that.
According to Twitter user @nurfitriainii, it's because some vending and parking machines only accept bank notes bearing the signature of former Bank Negara governor Dr. Zeti Aziz.
Aini told SAYS that she learnt about the "glitch" from a staffer at Taman Botani Putrajaya.
"I was about to buy a drink from a vending machine, but it won't accept my RM1. So I asked a guy who works there if he has any other RM1 notes," she said.
"That's when he told me that the machine won’t accept Muhammad bin Ibrahim bank notes. I was shocked as well, so I tested it out and it was proven to be true."
Aini's tweet proved to be a moment of enlightenment for netizens, some of whom said they'd always thought it was because the notes were too crumpled or they'd somehow gotten hold of fake notes
Someone even posted a notice of a machine that specifically "asked" for bank notes bearing Dr. Zeti Aziz's signature
Highlighting that this only applies to some machines, Aini - who is a former software engineer - noted that the "glitch" is likely to occur in machines that have not been updated by its manufacturer or programmer
"Each vending machine comes with a firmware, where all the coding is stored by the programmer. The machine has been programmed to accept certain patterns of bank notes, and as a user inserts their bank note, the note acceptor will scan the design and match it with the design stored in the firmware," Aini explained.
"There are some other factors as well, such as size. Same goes to coins, where it detects the diameter, thickness, and ridges," she added.
Looks like we all learnt something new today!