While the townscats of Whiskerton delighted in uncertainty, they were privy to their own quirks and inclinations, and rather finicky about their preferences. Arya, for instance, preferred sunbathing spots with a twinge of sponginess to them, like a hard pillow or a stack of papers. If a spot didn’t meet her standards, she’d dispel a tragic sigh. There was a cat named Mowgli who took his bird watching seriously—he was known to yawp at anyone who dared talk while his eyes followed the feathered creatures’ movements. Another cat, Poh, would yawp at anyone who didn’t talk to him while he watched birds.
Luna’s particular quirk was to begin each day with something that captivated her, something that kept boredom at bay, something that made her wiggle with glee. On most days, that meant darting about the town to identify changes made overnight; the town of Whiskerton would occasionally rearrange itself at night, unbeknownst to anyone until the morning after, save for the occasional cat on a midnight stroll.
Each morning before breakfast—since to her there were more important things than food—Luna would zoom through the streets to discover changes. Blinded by curiosity and sprinting far more quickly than she had any business to, she’d bump into hawker carts and morning walkers and mail deliverers, drawing curses in her wake.
On this specific morning, Luna found, much to her chagrin, that the streets and trees and rocks and grass had decided to stay exactly where they were. Not one to stay chagrined or bored or otherwise unoccupied for long, she turned to her next favorite thing: pranks.
And one prank that never got old was ringing doorbells.
Specifically, ringing Blade’s doorbell, as he was a cat who startled easily. Whenever someone rang his doorbell, a bang! could be heard from somewhere within his cottage, for he’d leap high enough to hit the ceiling. Luna, along with any kittens accompanying her, would giggle, then bolt before Blade opened the door.
Now, it wasn’t only Blade’s skittishness that made ringing his doorbell interesting. A Whiskertese doorbell was itself an entertaining contraption, being more extraordinary than an ordinary doorbell. The contraption had been Arya’s idea—she was clever at that sort of thing—and Blade, as her best friend, was clever at bringing Arya’s ideas to life.
The Whiskertese doorbells were fabricated like so: two marbles were connected by something called an entangler, which, true to its name, entangled the marbles. This meant if someone looked directly at one marble, then the second marble would immediately be affected—without anyone having looked at it! Each of the two marbles would be in a superposition of red and blue, but once someone observed one of them, the two marbles would turn the same color: either both red, or both blue.
An entangler was embedded into the front door of each home, and the two marbles were placed in compartments that hung on either side. The compartment on the outside had a peephole through which a visiting cat could observe the marble. This act would immediately affect its counterpart on the other side of the door. The second marble was connected to a sound box so that whenever it became a single color, the sound would go off.
The adult townscats loved their doorbells, but the kittens loved them even more. Luna, especially, relished in how she could immediately change the state of a marble without having looked at it by gazing at another marble. And in how that change released a chiming sound to summon a cottage’s occupant.
With doorbells and Blade and marvelous sounds foremost in her mind, Luna went in search of an accomplice. She happened upon Soya, a timid but curious black kitten with a white diamond on her chest, who adored rustling plastic and reclining on high perches. Soya was attempting to climb her way up the side of Town Hall for a bit of reclining when Luna found her.
“Hihihi,” Luna called. “Up for some mischief, Soya?” Soya, being a kitten, was of course always up for some mischief. Not moments later, the two scurried towards a certain buildercat’s home.
Unsuspecting Blade was in his kitchen, staring intently at a suspicious spot on his ceiling. He clutched a small parcel in a paw because he was supposed to be delivering a custom build to one of the townscats, but he couldn’t tear his eyes away from that spot. He just had to figure out what it was!
Meanwhile, on the front porch, Luna nudged Soya to peer inside the bell compartment. The marble within turned blue, as did the marble on the other side of the door, and the doorbell rang.
The sound was, unsurprisingly, accompanied by a loud bang! and a “Twisted yarn!” which launched the kittens into fits of giggles.
True to his nature, Blade had leapt reflexively at the sudden peal, bopping his head on the ceiling. Unbeknownst to him, the suspicious spot had transferred itself to his forehead in the process. Transferred itself, because the suspicious spot was in reality a ladybug who had, in the spur of the moment, decided to test whether perching on a cat’s head was more fun than perching on a ceiling.
Blade glared and grumbled—first at bopping his head and then at the now-blank ceiling—before heading to the front door.
When he opened the door to an empty porch, he groaned. Infernal kittens, I bet it was them. Disturbing my suspicious spot scrutinization. Now I know how Mowgli feels when he watches birds.
From where they hid behind a bush, Luna and Soya shared gleeful whispers and watched as the buildercat glared at the street before trudging back inside. Ringing Blade’s doorbell had been so much fun, they decided to have another go of it.
“Let’s count to five and then ring again,” Luna said. Entanglers always took a few seconds to re-entangle the marbles once set off.
Soya nodded, and began to count: “One.”
“Two,” said Luna.
“Eight.”
“Butterfly!”
“Where?”
“There.”
“Eee! Catch it, catch it! Left. No, right! Rightleft!”
Luna attempted to snatch a glimmering butterfly from the air, Soya contributing unhelpful albeit enthusiastic remarks. They spent a few breezy moments like this before Luna remembered why they were there.
“Wait,” Luna said. “Let’s ring the bell first and then catch it?”
Soya saluted.
They rang the doorbell once more; this time it was Luna who peered into the peephole. The marble turned red, and the ensuing bang! they heard from within delighted them so fiercely they forgot all about the butterfly.
The ladybug, peeved by the sudden jolt, hopped back to the ceiling, concluding that cat heads were decidedly not ideal for perching after all. But Blade did not see the suspicious spot reappear above him, for he barreled to the front door, furious.
He flung open the door, unsurprised to find no one there, and yowled into the mid-morning sunshine: “I know it’s you, Luna! You and whichever kittens you’ve roped into bothering me. Leave me alone or I’ll… I’ll…” he glanced at the parcel still clutched in his paw. “I’ll make you run an errand!”
There was no answer, though he hadn’t really been expecting one. But he had a plan.
He pretended, with inimitable dramatic flair, to close the door. He left it a smidge open, just enough for him to peep through.
However, Luna, being somewhat of a connoisseur of plans and pranks, anticipated this, so she turned to Soya and said:
“It’s your turn to ring the bell. Go up there! I’ll stand guard.” And when the diamond-chested, gullible kitten did just that, Luna slipped away, rapturous at this bonus prank, the sounds of a disgruntled cat berating a kitten fading behind her as she fled.
Back on the porch, beration complete, Blade pushed his parcel into a regretful Soya’s paws and set her about making the delivery. Which meant he was completely free to ponder the suspicious spot in peace.
Chapter 3 Part 2 - Commentary - Multiple Qubits, Entanglement, and Bell States