《列子·说符》
意念明显地倾注于某一点时，即便碰到了树桩或地坑，脑袋撞到了树干，自己也觉察不到。
意之所属著，其行足踬株埳，头抵植木，而不自知也。
When a person’s thoughts are focused on a certain point, even if he bumps into tree stumps or holes in the ground, or if his head smashes into tree trunks, he does not even notice.