Elements in a picture look more natural and three-dimensional when they're overlapped. This painting by Henry Herbert LaThangue (1859-1929) suffers from a lack of overlapping. We see the shape of each goose pretty much in its entirety, just touching the next one.
LaThangue commits the same foul in this picture, which is full of tangencies. A tangency is a point of contact between one shape and another so that they just touch without overlapping. The front goat seems to be nibbling the leg of the one behind it, and the third one back is nibbling the second one's shoulder. The effect of both pictures is awkward, flat, and spotty.
This painting by Charles Sprague Pearce (1851-1914) is much more successful in this respect. The sheep form an interesting mass, yet still have individual identity. Some of them are hidden behind the shepherd or partly cropped off the edge.
Related post: Tangencies