Locals joke that Yemeni trees are actually blue and red, the color of the plastic bags that you get when you buy qat, a mildly narcotic leaf, and the Yemeni national past time.

VOA: standard.2010.04.01

We receive the electric signals from each tip, we tell which neuron is listening to, we get that color piece.

我们从每个电极端接收到电子信号，我们说明去听哪个神经元，这样就得到了一张彩色图片。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选

As I say, red tends to be chosen, but then if you get lab experiments showing that that particular color of gas blue is somehow or another sort of more invasive of your consciousness than red is, then you move away from the arbitrariness of the choice of red as a color.

所以人们就倾向于选择红灯，但是如果你想用实验证明,比如说烟蓝色或者,其他任何另一种颜色比红色更加醒目，那么你就忽视了颜色选择上的任意性。

耶鲁公开课 - 文学理论导论课程节选