A common visual shorthand to indicate that a character is smart is to have them play Chess, Go, or some similar game. After all, Sesquipedalian Loquacious dialog can disrupt pacing, and not everyone is a chalkboard-toting professor, but it's unobtrusively easy to insert a chessboard into a scene. The character doesn't even have to actually play it; simply lingering nearby with a concentrated gaze is enough to suggest deep thinking. If the normally very bookish character really loses his temper, he might end up Flipping the Table instead. Examples of Smart People Play Chess include: