The anomaly

Why won’t you fit? No matter which way I move you, turn you, flip you, bend you, flex you, stretch you, squeeze you, grip you. What a baffling anomaly. For all accounts there shouldn’t be a problem fitting into the allotted space, unless all my senses deceive me. The shape seems right. Smooth edges, no apparent blemishes, at least on the surface. By all appearances the small device is indeed, perfectly rounded. Just as intended, just as initially planned. Lightweight and easy to hold. There is no reason it shouldn’t work. My word, it is enough to send a mind into chaos! There was no issue in the build. Proper protocol was followed during each stage of creation. Of course it was, success depended on it. I simply cannot understand it. Everything appears normal. Maybe there is something wrong with the opening. Naturally I have checked it – one must always ensure due diligence, but perhaps it warrants another look. However the slot, upon further inspection, proves to have nothing wrong with it either. Not a single flaw. Not a single crack. Nothing. Completely unfathomable. By design, it is perfectly measured to your dimensions, and yours to its. All the others have been positioned and stored on their first attempt at insertion. What mysterious defect could there be, that this, which has undergone the very same treatment as the rest, should break the mould?