how leaf cells and lower level parent cells of the existing artwork can be used in a new piece of semiconductor artwork in describing this process reference is made to fig3 a 3 c after the process is initiated with the start step 160 and a leaf cell 80 to be searched for in the existing artwork is input by the user via input device 4 step 170 then questions whether the leaf cell 80 is valid the leaf cell 80 would not be valid if it did not exist in the database 7 of the software that generates the existing piece of artwork from which the leaf cell 80 is being ported step 170 is included as a u201c sanity check u201d to make sure that the process will flow correctly if a user inputted an incorrect leaf cell 80 name the name would not be found and the process can return an error message after skipping directly to the end of the flowchart this check makes sure that the leaf cell 80 is actually in the database 7 and that there is an artwork representation for it the process illustrated in fig5 allows a user to input many options via input device 4 including which top level parent tlp of the existing artwork constitutes the boundary of the search for leaf cells step 180 of the flowchart determines whether the tlp cell over which to search has been specified with reference to fig3 a 3 c a user may wish to find all of the instances that leaf cells 80 appear in chip1 150 or may want to restrict the search to blocka 120 or even to subblocka2 100 one reason to allow.