Thought writing is also known as ideography. The symbols that make up an ideographic script are ideograms.
An ideogram represents the drawing of an idea. An ideographic mark might not spell or depict anything directly, but will nevertheless be widely understood.
Many ideograms act as short cuts in communication, enabling us to replace a whole word or phrase with a single mark. Right and wrong can be communicated using simple symbols.
Like many pictograms, ideograms are often meant to be understood across the boundaries of language. For example, numbers are very widely used and recognised but are written very differently in different languages.
The Chinese script is an ideographic form of writing, the earliest known examples of which date from around 1400-1200 BC. Some characters in the Chinese script are formed from ideas conveyed by stylised drawings, themselves developed from early pictograms.
Chinese script is highly complex and has up to 50,000 characters. When much of the world began to use typewriters, this enormous number of characters presented a logistical problem - it would take an enormous machine to accommodate them all.
The need to find an alternative to typewriting contributed to Japan's development of the fax. Remember the Japanese writing system was originally adapted from Chinese characters. It is equally complex - in their first six years of school Japanese children have to learn 881 characters. The invention of the fax allowed handwriting to be used in business, and enabled written communication to travel across great distances.
Chinese characters are not tied to a particular spoken language. People throughout China (and in the past in Japan, Korea and Vietnam) use and understand Chinese script, although they might not understand each other's speech. Chinese script remains the oldest writing system still in use.