三人行必有壹電燈泡
[sān rén xíng bì yŏu yī diàn dēng pào]
The name '三人行必有壹電燈泡' literally translates to 'In a group of three people, there must be one light bulb.' It's a play on the traditional Chinese saying '三人行必有我师', meaning 'Among any three people walking together, one can be my teacher.' Here it humorously suggests that in any group setting, someone always feels like a third wheel or an unnecessary person.