Abstract: A method of forming one or more features on a working surface of a superhard carbonaceous material comprises: positioning an electrode plate adjacent the superhard carbonaceous material, the electrode plate having an electrode surface oriented toward the working surface of the superhard carbonaceous material, the electrode surface including at least one protrusion or indentation formed therein or thereon; moving the electrode plate and the working surface toward one another while removing material from the working surface via electro-discharge machining; and moving the electrode plate and the working surface laterally relative to one another while removing material from the working surface via electro-discharge machining.