Iron rusts from disuse; water loses its purity from stagnation ... even so does inaction sap the vigour of the mind.

Iron rusts from disuse; water loses its purity from stagnation ... even so does inaction sap the vigour of the mind.

铁因废弃而生锈;水因为停滞而失去了它的纯净。即便如此，不作为也会削弱头脑的活力。

-- Leonardo di ser Piero da Vinci 达芬奇爵士