The Staircase
Nine bars of grey, each one step lighter than the last.
这个体验还没有翻译，所以文字仍是英文。
玩法
先看，再回答
Nine bars of grey, each one step lighter than the last.
- 不到一分钟 · 1 个问题 · 然后是解释
原理 — 建议试过之后再读
Edges, sharpened
Every bar is a single flat grey. Where two bars meet, the lighter one looks lighter still along the edge and the darker one darker still — thin bands that are not in the picture.
The physicist Ernst Mach described them in 1865. Here the old explanation holds up: cells in the retina are held back by their neighbours, which exaggerates any step in brightness, and so the visual system sharpens edges before anything else sees them.