Samuri Jack questions

Cafe Society
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1.In the Samuri Jack cartoons his symbol (don’t know if it’s his personally or his family/clan) is a circle with four inward strokes. Is this an actual Japanese syllable/pictograph, and if so what does it mean?

  1. In episode 18 he defeats the uber-robots with the help of the nerdy scientist who created them. I swear it’s the same voice as the nerdy scientist on The Simpsons, but can someone who’s caught the credits confirm this?
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  1. It looks like Jeff Glen Bennett is the scientist whereas Frink is played by Hank Azaria. Certainly though Jeff must have taken inspiration from Hank.