设计灵感来源于视力表，用动物的脚印替代字母。根据国际自然保护联盟濒危物种红色名录（IUCN红色名录、红皮书）对物种的分类级别，设计内容由无危、近危、易危、濒危、极危、灭绝几个部分组成。越往下脚印越小，大小递减代表着物种的濒危程度，甚至灭绝。旨在传达物种多样性对于人类的重要程度，呼吁人们关注“物种濒危”这一现实问题。

The design is inspired by eyesight chart, and replace the letters with footprints of animals. According to IUCN Red List, there are several categories of species, so the chart is divided into no danger, near danger, vulnerable, endangered, critically endangered, extinct. The footprints are smaller when the chart goes down to represent the situation of the animals are facing, to raise people’s awareness to protect endangered animals.