This way, I implicitly defined the outside of the cube as the front face and the inside as the back face.

通过这样的方式，也就隐式地将立方体的外部定义为正面，而将内部作为背面。

youdao

A badly sunburned face or back is extremely painful.

严重晒伤了的脸或背部是非常疼痛的。

《柯林斯英汉双解大词典》

Face facts —she isn't coming back.

面对现实吧—她不会回来了。

《牛津词典》

The expression probably comes from the physical act of turning your back toward someone, instead of speaking to him face-to-face.

VOA: special.2009.12.13

And the head you are seeing at the back there he was trying to touch is his wife's face.

他用手于去触摸的那个人,是他的妻子。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选

the face being drawn back in a universal expression that every human everywhere would be able to recognize.

用一种普遍的面部表情，脸被后拉,任何地点，任何人都能辨认。

耶鲁公开课 - 心理学导论课程节选

Durant suffered several serious injuries, including a broken back and face and leg wounds.

CNN: Videos of POWs a staple of war propaganda

He added the most serious injury was to a female member of staff who was punched in the back and face.

BBC: Morton Hall Immigration Centre

His family in the UK have called on the British government to bring him back to face a trial under the UK judicial system.

BBC: Ex-soldier Danny Fitzsimons awaits Iraq murder verdict