'Crossed Wires' by Katharine Seymour

She looks out onto the garden scene, enclosed by a box-hedge, tall against an overcast off-white sky, but does not see it. Instead, she sees a chin of images that constantly change. She tries to hold onto one, to grab it forcefully between the imaginary forceps of her mind, and hold it there, so she can examine it, see it more clearly - but she can't, and this upsets her.