双向图（ambigram，或叫inversion、 flipscript）不只是把字语对换的形式，而是从不同方向也可以阅读、图形式的文本。双向图可以是一些字组成的，方向不同、字相同型式的双向图比较多，不过也有方向不同、字也不同型式的双向图。侯世达也把双向图描述为「把两种不同读法字挤进同一个曲线的的笔记体设计」（calligraphic design that manages to squeeze two different readings into the selfsame set of curves.）。

An ambigram is a word, art form or other symbolic representation whose elements retain meaning when viewed or interpreted from a different direction, perspective, or orientation.

The meaning of the ambigram may either change, or remain the same, when viewed or interpreted from different perspectives.