Ghost of a flea

I saw that and thought it amazing. The naturalist's eye in the work was the most impressive thing capturing just the scene before him. I remember seeing a medieval German painting I think at the British museum that was inexplicable a realist scene of a corner of a building and plants in proper perspective and accurate botanical detail. The painter capability was a stylistic dead-end and his/her identity unknown. Just a recording of what was before the painter's eye.