A proposition or general reflection —"Art is long and time is fleeting."

This motive takes the form of a state 
ment to be explained or amplified. In the example quoted below the general statement or proposition is expressed in the first sentence :
The first thing to be required of a building— not, observe, the highest thing, but the first — is that it shall answer its purposes completely, permanently, and at the smallest expense. If it is a house, it should be just of the size convenient for its owner, containing exactly the kind and number of rooms that he wants, with exactly the number of windows he wants, put in the places that he wants. If it is a church, it should be just large enough for its congregation, and of such shape and disposition as shall make them comfortable in it and let them hear well in it.
•	— joHN Rusxix, Architecture and Painting.
SUGGESTIONS.- The proposition is here developed by the use of illustrations as material .
" If it is a house . . . . that he wants."
"If it is a church . . . . hear well in it."
This use of illustrations is called exfiosition by exemfilificatthn.