What pencils are used to write on glass such as in the film A Beautiful Mind?

Answer 1

the writing utensils used in the film to draw on glass in several scenes were most likely wax pencils (same as grease pencils). These are ideal for use in a laboratory setting as they mark well on glossy hard surfaces such as glassware and are generally resistant to water and other liquids. generally they can be erased by wiping with a clean dry paper or towel of some sort. These pencils come in a variety of forms and colors. For more information, see the link provided.

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