Speculative carving: an undocumented practice of seventeenth-century workshops.

Carved lengths of timber are occasionally found in the undersides of pieces of English seventeenth-century furniture for which they were obviously not intended. David Knell illustrates a gateleg table and a chest of drawers with this feature, and comments about the table:

 
An interesting feature is the obvious re-use of timber from another 
item, as shown by the carved lunette decoration on the inside of one of 
the stretchers, which the joiner did not take the trouble to plane off. 
The carving may be up to a bundred years earlier than the table of which 
it now forms part. Good seasoned timber was seldom wasted and evidence 
of re-used wood occurs many times on period ...