Unfortunately, Eliza, a bit too prosaic. The stool happens to be one of those with a button top which divides its surface into 16 clearly defined convex sections. Anything over 4 inches in length, even if identically coloured, would be instantly visible on it, as it would lie across the segments. & this was not self-, but contrasting, colour. It was not by artificial light: the spotlights were lit for the corners of the room; but this stool is not in a corner, but on open floor. I repeat, it was mid-afternoon after the clocks had gone forward.

Not "prickly", exactly; but not over the moon at being told that I can't distinguish a clear surface from one with an easily identifiable object lying on it in broad daylight. Whatever the explanation, I do not warm to the one that states that it must be that I, my wife, and two of our friends, are all so bloody stupid, & of such grossly defective vision, that we can't see what is manifestly before our eyes in the middle of the room at 4 o'clock on a fine Spring afternoon.

Would you be?