a optical illusion

The "halo cloud" was just an optical illusion caused by sunlight hitting a cloud at just the right Angle.

“光环云”是由阳光以恰到好处的角度触及云层而引起的一种光学错觉。

Mirror tic Tac Toe by Peleg Design is a rad little optical illusion board game with half o's and X's that only are complete when put in play.

佩莱格设计的镜面井字游戏是一个超赞的迷你视觉幻想棋盘游戏，半o半x的棋子只有在玩起来放在棋盘上的时候才完整。

In a second optical illusion, the Ponzo illusion, the volunteers were shown two identically sized circles superimposed onto the image of a tunnel.

第二个是蓬佐错觉，志愿者可以看见在一条隧道的图像上有两个大小一模一样的圆。