She looked at the linoleum floor, grey blue with streaks of white and a darker, matte, blue. What she saw was not the floor, however. It was the light.
The midday sun shone through the large windows, making rectangular splotches of white, interrupted by blue bars, refracted into unsteadiness. The effect was not simply squares of light on a linoleum floor; you could go down, see through the floor, step into another world.
Which is exactly what she did. She lay back in her chair, let the piano course through her veins, felt herself fall through the floor, felt the ripple when she passed from our world into theirs.
She opened her eyes, looked at a world made entirely of white light. She could still hear the faint music from above, smiled because she knew that it was music that no one else had heard before. She pretended that it was for her, though she knew better. Still, she had an endless stage and no audience. She became the ballerina of her childhood dreams. She capered, careened and cavorted, flitted, frolicked and gamboled, leaped, pranced and promenaded, spun, swayed and swung, twisted, waltzed and whirled. There was nothing but her, the music, and a sea of white light, with something that could have been windows on one end.
Above her, someone walked to the chair she'd been sitting in, listened to the musician. If he'd known how to look, he would have seen her there, dancing. But his eyes could not see. They noted the reflections, saw the footprint marring one of them, the scratches and streaks across the others. Had his eyes been able to see, they would have known them to be not dirt on the floor, but footprints and tracks outside the window in the next world.
She didn't notice the tracks either, she was interested only in the light. They were old anyway, memories of other wanderers who'd become trapped. The music stopped, and she faltered, realized that there was nothing but distorted windows and light. She looked up, but couldn't find the floor.
Panic struck. What the hell had she been thinking? How long had she spent, dancing in a room made of light? She'd been seduced by its nature, and woken up much later, only to wonder what had happened. There was no ceiling, no window into the world above. She walked to the inverted versions below. The tracks were still there, of all shapes and kinds. There was no door, only the windows. She took a last lingering look at the room, what had been her stage for moment or two. A stray note trickled through the floor, and she smiled wistfully at what lay above.
She turned back, turned her back to the shapeless white light. And stepped through the window, outside the transition, right into another world.
See part two at If it had been able to, the light would have smiled.