On the usability of number pads

I'm not thick. I know it doesn't sound like much of a boast, but I'm pretty competent at this whole adulting lark. But it appeared that I had forgotten a 4 digit number I'd set up less than a minute ago!

The security guard smiled wearily at me, "It happens to everyone!" She said. Which, I'll admit was of small comfort.

Work had taken the (sensible) decision that our entry cards weren't secure enough. In order to gain access to the building we needed to present our card and type in a 4 digital personal PIN number¹. Only then would the gates open.

I shuffled back to the long line of people setting up their PINs and texted my boss to let them know I was stuck at security.

I got to the front of the queue, swiped my card, and typed my new PIN on the keyboard numpad. Rather than my date of birth, or the first few digits of π, I chose a pattern - 2684 - nice and easy to draw. No way would I forget that²!

I wandered to the gate, swiped my card, and confidently punched in the patter on the PIN pad.

A red light flashed and a buzzer sounded. I let out an audible swear word. The people behind me, who were also late for their meetings, stared at the absolute cretin in front of them. A moron who forgot a 4 digit number in the 10 seconds it took to walk from one end of the reception to the other.

The guard wandered over. "It happens to everyone. Look at the numbers," she said.

And so I did. The PIN pad had been installed with a privacy shield so that miscreants couldn't see what your fingers were doing. It had the side effect of blocking tall people like me from seeing the pad. So I crouched and looked.

This was the number pad I had to use to get through the door:

But this was the number pad I'd used to set up my PIN:

FFS!

There's an excellent explainer of how the touch-tone telephone got its button order - and another on why it is different from the calculator layout.

In the end, I just set my PIN to the ambidextrous 4564³.