主权项 |
1. An apparatus comprising:
a working surface including at least one material removal member, the material removal member being configured to remove at least some of a first portion of a first material; and a protrusion extending outwardly from the working surface, the protrusion extending beyond the at least one material removal member by a first distance, the protrusion configured to inhibit the at least one material removal member from removing at least a second portion of the first material, the second portion having a thickness substantially equal to the first distance.
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