What components in this painting create an illusion of a line?

Line is a visual element of art, however, in a painting, a line can be created using shape and form using perspective and scale to create a line within the painting frame, this may recede in any direction of the painting plain. 

Howard ruffo  makes the reader feel that ellery has misidentified who is responsible for committing the crime and will end up feeling embarrassed.

Gouges, because, like there named, they gage the amount of space an object has to move around.hope this : )