11

My mind reels as I spin towards the dark sphere, the size of it growing larger and larger until it almost fills my vision. Everything is spiralling around this black hole in a kaleidoscope of colours, the shapes of things stretched and distorted as they curve around the void. Ahead of me, I see Dad’s toothbrush stretched impossibly thin, its colour shifting from blue to red as it seems to freeze on the edge of the darkness.

I can feel myself being stretched in the same way, the immense gravity pulling at every atom of my being. It’s like I’m being torn apart. All I can see is the darkness now; everything else a distant blur of distortion at the very edge of my vision.

Things are speeding up.

The dark globe surrounds me now. It’s as though I’m inside and outside of it at the same time, the confusion inside my brain stretched to breaking point as I slip over the edge. I’m falling into infinity and I don’t know if I’ll ever stop.

And then in the darkness I see a dome of light squeezed into a narrowing point. I’m hurtling towards it and now this blinding light is all I can see. I’m going to hit—

I close my eyes, waiting for an impact that never comes and then I open them again to find that everything has changed.

I’m standing on the stairs that lead to Lily’s room.

There’s no dark globe. There’s no point of blinding light. The crushing force I felt pulling me apart is gone.

There’s just the stairs that lead to my sister’s bedroom. And I’m halfway up.

Einstein’s theory of gravity explains the movement of every star and planet in the sky and predicts how wormholes could connect two points in space-time. A bridge across the universe or a shortcut from the bathroom to the stairs. That’s the only way I can explain how I’m standing here.

I start to bound up the stairs, desperate to see if Lily’s in her room, but as I look up I realise that this nightmare isn’t over yet.

At the top of the stairs I can’t see the door to Lily’s bedroom. In fact, I can’t even see the top of the stairs, just an endless sequence of steps stretching on forever.

I freeze, swaying in confusion as a wave of nausea rises up inside me again. Glancing back over my shoulder, I see the same picture in reverse, the steps leading down in a never-ending staircase.

I turn back, fear thumping in my chest as I try to make sense of it all. I start to climb, thinking that this must be some kind of optical illusion – like that picture of an impossible staircase that I saw when Mrs Bradbury took me to the art gallery.

Most of the time, Mrs Bradbury taught me at home. We’d sit at the kitchen table with a textbook open between us as we talked about life, the universe and everything. But sometimes Mrs Bradbury took me on field trips too.

There was this exhibition on at the local gallery by an artist called M. C. Escher and Mrs Bradbury reckoned it would help me with my geometry.

“Escher said he was a ‘reality enthusiast’,” Mrs Bradbury explained as we walked around the gallery. “His art speaks in the language of mathematics and science to show us a picture of the universe.”

I think about the pictures we’ve seen so far – lizards crawling out of jigsaw puzzles, strange patterns of birds and fish, a single eye staring out towards us with a reflection of a skull inside.

“He had a pretty weird view of reality.”

Mrs Bradbury laughed.

“Well, the universe is a pretty weird place,” she agreed.

There was a group of schoolchildren standing around the next picture, so we had to wait for them to move on before we could see it. They looked about Lily’s age, all wearing the same maroon school uniforms, although some of the girls seemed to have found ways of accessorising these to make them look cooler. As their teacher finished talking about the picture and led them on to the next one, calling out to a couple of girls at the back to stop chatting and keep up, I couldn’t help feeling jealous of them. I mean, I love learning stuff with Mrs Bradbury, but sometimes I think being “academically gifted” means I’ve missed out on the chance to have friends.

“What do you think of this one then?” Mrs Bradbury asked as we stood in front of the picture.

It was a black-and-white drawing of an old-fashioned building, the picture showing a bird’s-eye view. My eye was immediately drawn to the central staircase at the top of the building, its steps arranged in the shape of a square. A group of creepy-looking men, all dressed in hoods, were walking up and down passing each other on the stairs. But as I stared at this scene, my brain started to rebel as I tried to work out what was wrong.

“Where does the staircase go?” I asked. “They’re walking up and down at the same time.”

Mrs Bradbury smiled.

“Well done, Maisie. The title of this picture is Ascending and Descending, but most people call it the impossible staircase.”

Stepping forward, her finger hovered above the surface of the picture, tracing the path of the hooded figures as they climbed the stairs. Each turn seemed to take them higher or lower depending on the direction they were facing, but as Mrs Bradbury’s finger finished tracing the fourth side of the staircase it arrived again at the point where she’d started from.

“The staircase is never-ending,” she explained. “Nobody will ever reach the top. It’s an optical illusion, but Escher based this picture on a shape that was created by a mathematician and a scientist. It’s an impossible object – something that can’t exist in the three-dimensional world in which we live, but geometry allows us to create shapes in four or more dimensions. We have to use equations to describe these shapes because we can’t draw them on paper or model them out of plasticine. But according to maths they’re as real as a triangle or a cube.”

Mrs Bradbury’s words echo in my head as my feet pound up the stairs. Real… Impossible… Neverending… I keep climbing, straining my eyes for a glimpse of the top of the stairs, but it never comes.

Panicking, I double-back on myself, desperate to find a way out. My feet thunder down the steps, the same sound I hear every morning when Lily gets out of bed and comes downstairs. But instead of arriving at the landing after a dozen or so steps, the stairs just carry on, step after step after step. I can’t stand it.

I remember how, when the kitchen seemed to be expanding around me, all I had to do to escape was close my eyes and turn the door handle. Maybe that’s what I’ve got to do now. If what my eyes are showing me is impossible, then I need to trust my other senses to find a way out.

My hand is shaking as I grab hold of the stair-rail. Closing my eyes, I start to climb again, slower this time, counting every step as I go. One, two, three, four… If I’m right, I just need to focus on what must be real, the worn fibres of the carpet under my bare feet, the polished stair-rail sliding beneath my hand as I climb. Eight, nine, ten, eleven… Only a few more steps until I make it to Lily’s room.

I remember her voice echoing on the other end of the line. “I’m so sorry. I’m going to put things ri—” Lily’s words were cut off mid-sentence, but if I can make it to the top then maybe I can find Lily and she can keep her promise to me.

But the steps keep on coming. Fourteen, fifteen, sixteen, seventeen… My footsteps start to falter, the sound of my heart thumping loudly in my chest as I realise what this means. Nineteen, twenty, twenty-one…

I can’t wait any longer.

I open my eyes and my heart breaks in two.

All I can see is an endless sequence of steps rising up ahead of me. The stairs go on forever.

Letting go of the stair-rail, I sink to my knees. I can’t stop myself from sobbing as a fresh wave of despair overwhelms me.

This is my house. These are the stairs to Lily’s room. But I’m never going to get there.

I feel like giving up and rushing down the stairs to surrender to the emptiness that’s devoured my home. But I can’t even do that any more as the stairs stretch endlessly in both directions. I’m going to be trapped here forever.

A fresh wave of sobs shake my body. All I want is my family back.

Then, through my tears, I glimpse a figure on the step beside me. Glancing up, I see … another me. The same lilac dressing gown that I’m wearing, my own face fixed on the stairs straight ahead as I’m frozen in the act of climbing them. And in front of this other Maisie, I see another and another and another, an endless line of Maisies heading in both directions on the stairs.

Each one is frozen in a moment of time and, as I glance back down the stairs, I see more – an infinity of Maisies climbing up and down. It’s as though I’m endlessly ascending and descending – just like the people in that picture at the art gallery.

I reach out towards the Maisie who’s closest to me, but my hand just passes straight through her, the figure only visible when it’s refracted through my tears.

This doesn’t make any sense. How can I be everywhere, but stuck going nowhere?

My mind rebels. People can’t be in more than one place at the same time, but then my brain reminds me what can.

Everything in the universe is made of tiny particles. The stars in the sky and the molecules inside my body are all made out of atoms. Every atom consists of even smaller particles: protons, neutrons and electrons. But when these electrons move around it’s impossible for scientists to work out exactly where they are. All they can do is calculate the probability of finding an electron in a specific place.

But this is where it gets really weird. To work out the probability of finding the electron in a particular place, scientists have to calculate every possible route it could have taken to get to that precise spot. That’s the only way they can get the right answer. It’s as though the electron travels by every possible path at the same time.

The electron is everywhere at once – just like me.

Through my tears, I stare at the never-ending Maisies climbing up and down the stairs.

But I’m a person – not a subatomic particle.

Choking back another sob, I try to catch my breath. It feels like I’m hyperventilating, my heart pounding in my chest as I try to work out what this means.

Sliding my right hand beneath my dressing gown, I hold it against the centre of myself, trying to focus on this one thing to calm my racing heart.

And that’s when I notice something really strange.

Your heart sits in the centre of your chest, but slightly on the left. But as my heartbeat thuds against my fingers it feels like mine is on the right. I move my hand from left to right, trying to find the place where my heartbeat feels strongest, but this is definitely on the right.

My heart’s in the wrong place.

I can’t hold it together any more, my gulping sobs turning into hysterical laughter. How can my heart be on the wrong side of my body? Just another item to add to my list of impossible things, along with an infinity of Maisies and stairs that never end.

Then I remember another almost impossible object that Mrs Bradbury showed me when we got back from the art gallery.

“A normal piece of paper has two sides,” Mrs Bradbury said, tearing a strip from the topmost sheet of her A4 pad. She turned this strip of paper over in her hands. “The front and the back. But if I take this strip of paper, give it a twist and then join the ends together I’ve created a Möbius strip.”

“What’s a Möbius strip?” I asked as I watched my tutor tape the two ends together.

“It resembles the scientific symbol for infinity,” she replied. “A Möbius strip is an infinite loop that you can never escape from.” Mrs Bradbury handed me the twisted loop of paper that she’d made. “Find out for yourself. I want you to draw a line down the centre of the strip and don’t stop until you reach the point you started from.”

Feeling a bit puzzled, I picked up my pencil and, resting the Möbius strip on the table, started to draw a line down the centre of the strip. As the paper looped around, my pencil followed it, the line I was drawing crossing over the band of tape that Mrs Bradbury had used to join the ends together not once but twice, before reaching the start of the line again.

“There you go.”

I started to hand the strip of paper back to Mrs Bradbury, but she shook her head.

“Take a closer look,” she said. “How many sides does the strip of paper have now?”

I turned the Möbius strip over in my hand. The line that I’d drawn seemed to cover both sides of the twisted loop, but looking closer I realised that I was wrong.

“It’s only got one side,” I replied.

Mrs Bradbury nodded her head, a proud smile lighting up her face.

“The Möbius strip doesn’t have a front and back like a regular piece of paper, or an inside and outside like you’d find in an ordinary loop. The Möbius strip only has one side.” Taking the twisted loop of paper from me, she started to trace an imaginary path with the tip of her finger. “If you could walk around this loop of paper, you’d think that it never comes to an end. The only difference you’d find is that the features on one side of your body would switch over to the other side as you moved around the closed curve.”

Now, as my heart thuds beneath my fingertips, I realise what this means.

Maybe these stairs aren’t never-ending, but just twisted into a Möbius strip. I can’t ever reach the top or the bottom because I’m stuck in an infinite loop.

I picture myself turning the Möbius strip over in my hand, the one-sided shape existing only in two dimensions. There’s only one way to find the ends of the strip again – and that’s to tear the paper in two.

Reaching down I start to tug at the fraying carpet beneath my feet. At first it won’t shift, but then I find a loose bit on the underside of the stair and, as I pull on it, the carpet comes away, exposing the bare floorboards underneath.

Scientists have spent hundreds of years searching for the smallest building blocks that are used to build reality. First they thought it was atoms, then they discovered that atoms were made out of protons, electrons and neutrons, and then when they started smashing these together, they found even smaller particles with weird names like quarks and gluons. Every time science thinks it’s worked out what reality really is, it finds another layer of reality hiding underneath.

That’s what I’m looking for now. What’s hiding underneath.

Forcing my fingers into the gap between the floorboards, I try and prise them free. I feel the edge of the wood splinter against my fingernails, sharp jabs of pain forcing me to bite my lip. I pull with all my strength, but the floorboard doesn’t move – the nails holding it in place are firmly hammered down.

With a howl of frustration, I pull my hand free. I can’t take this any more – all the strangeness, the impossibility of everything that I’m experiencing. I just want to find out what’s really real…

I start to pound the bare floorboards, feeling the wood splinter and crack with every strike of my fist. The pain that I feel tells me this is real, but as the stairs cascade into infinity, I know this can’t be true. I catch the side of my little finger on the head of a nail near the floorboard’s edge, gouging out a chunk of skin. And as the droplets of blood fly through the air like tiny red balloons I watch reality splinter around me.

The floorboards beneath my feet dissolve into an inky blackness. The never-ending stairs with their long lines of Maisies disappear, leaving only an empty void behind. I screw my eyes shut, unable to comprehend this infinite blackness, and when I open them again I find myself standing at the door to Lily’s bedroom.

Then I hear her voice from inside.

“Come in.”