It was a short SF story from, I would be quite sure, pre 1970. It involved a young boy who had the ability to imagine what was the entire object, from just viewing/holding one small part of that object. The story involved his finding, or being given, a small foreign object found in a field (?) and him then extrapolating out to determine that this small component was from an alien space ship, which I think he portrayed in some way, can't recall how, maybe drew it or described it in detail. Can't remember how the story ended, but that was the main thrust - from small unrecognisable item, boy extrapolates out to alien spaceship. Does this story ring any bells with anybody please?