The grey pegasus filly sat in the hallway, concentrating on the tasks she'd been given.
"I'm just popping upstairs to tidy your sister's room darling," her mother had said, "do you think you could watch the muffins in the oven to check they don't burn?"
"Sure, mum," the young pony had replied.
"Right, it's about time I went and sorted out the garden," her father had announced, "the wisps are getting out of hand out there. Next door has such a nice flat piece of cloud, it makes our lawn look like an embarrassment. Would you keep an eye on your sister? She's playing in the living room."
"Of course, dad," the little pegasus had promised.
Two such responsible jobs. Derpy hadn't wanted to let mum and dad down. So she had sat in the hallway, the door to the living room on her left, and the door to the kitchen on her right.
She had turned to look at the oven. The muffins had been visible through the glass window in the front. They had looked like they were going to be delicious.
A crash had come from behind her, and Derpy had whipped her head around. It had been OK, the tower of wooden bricks her sister Ditzy was building had fallen over. No harm had been done, but it had worried her. She couldn't take her eyes off such a little foal for a minute!
But what about the muffins? Derpy loved muffins. She didn't want them to burn. "Oh what to do; what to do?!" thought Derpy Hooves.
And so the grey pegasus filly sat in the hallway, concentrating on the tasks she'd been given.
As she concentrated, something started to happen. Something really remarkable started to happen. Derpy's eyes started to drift apart. Her left eye focussed on her sweet little sister, playing happily in the living room. Her right eye focussed on the delicious looking muffins baking in the oven. In her mind, she could see both images, but it was like they were overlaid.
But still she sat and concentrated.
Derpy felt a bubbling sensation in her brain, and in an instant the two images separated in her mind. She could see both things so clearly. Her sister playing, and the muffins cooking. She couldn't see anything straight in front of her face, but she didn't need to.
"This is amazing!" she thought, "Why have I never been able to do this before? Can everypony do it?"
She sat and looked after her two responsibilities. The muffins were looking good. "They should come out of the oven now," thought the filly.
Keeping one eye on her younger sister, she edged sideways into the kitchen. "Ouch," she said, banging a hoof on the oven. She'd seen the oven there of course, but looking at anything with one eye can make it really difficult to judge distances.
She placed an oven glove on her hoof, carefully opened the door, and removed the baking tray. Shakily, she put the tray on the kitchen table.
"Thanks, dear!" Her mother's voice came out of nowhere. She was standing right in front of Derpy, but Derpy hadn't seen her because she hadn't been looking straight forwards.
Derpy's right eye swivelled towards her mother and Derpy's mother noticed her rather unusual expression. "What's happened to your EYES?!" she exclaimed.
"Oh, I had to watch the muffins and look after Ditzy Doo," explained Derpy nonchalantly, "so I used one eye for each."
Her mother was stunned, and didn't know what to say. She walked to the door, and scooped up her foal. "Well, OK," she remarked once her powers of speech had finally returned, "let's all have some muffins."
"Fresh baked muffins are the best," thought Derpy while scoffing down her second one.
The ponies heard the front door slam shut. Derpy rotated her right eye to see who had come in. It was her father. He trotted over to the table. "Ooh, what are we eating?" he said keenly.
Before anypony could answer, he shook Derpy by the shoulders. "Wow!" he said, "you're celebrating and you didn't call me in?!"
Everypony looked confused.
"Derpy's cutie mark!" he added.
Everypony stared at Derpy's little grey flank. "Bubbles?" Derpy's mum asked, "what do you think they represent?"
Derpy knew.