This is a table at our favorite restaurant. The right-hand edge is against the windows. Look carefully at the tabletop along this edge. The luster of the glossy tabletop has been worn down to a mat finish along this window edge. There is less wear, leaving a mat finish, at the corners of the table, closest and farthest from the camera. There is much more wear, along the window edge, in the middle. The rest of the table has a shiny glossy luster. The next picture shows us why:
The missing condiments appear!
Salt, pepper, cheese, and a container of sweeteners live most often near the middle of this window edge. After use, they are repeatedly returned to this central location along the window edge, leaving more wear (shown by the greater area of mat finish). Occasionally, they are slid to the corners of the table - perhaps to get them out of the way for plates of food or for cleaning the table for the next customers. This wears less off the glossy table top. Smaller regions of mat finish are left near the corners.
A subtle bell-shaped pattern of wear is left behind. More wear in the middle less along the corners.