2 by 4 is a common size of plank used in building and is in inches, until recently building materials were all in imperial system, now it's all gone metric.
Edit: sorry, I think 2 by 4 is in cms.
> Problem with that is that my foot could be 30 cm and your 10 cm, and it all falls down when you try to messure something with feet :P
Lol, your foot is 30 cm and mine is 10 cm, I like the way you put that. The thing is that most men's feet are about a foot with shoes on, so if you happen to have normal size feet then it's handy to measure something roughly by walking one foot in front of another. If you use metric then you have to multiply 30 by the number of footsteps which is not as handy. I was raised mainly on the metric system but later I got used to the imperial system and now find it easier to measure with. For example, I find 5 foot 9 1/4 easier to remember than 176 cms for some reason.
Edit: sorry, I think 2 by 4 is in cms.
> Problem with that is that my foot could be 30 cm and your 10 cm, and it all falls down when you try to messure something with feet :P
Lol, your foot is 30 cm and mine is 10 cm, I like the way you put that. The thing is that most men's feet are about a foot with shoes on, so if you happen to have normal size feet then it's handy to measure something roughly by walking one foot in front of another. If you use metric then you have to multiply 30 by the number of footsteps which is not as handy. I was raised mainly on the metric system but later I got used to the imperial system and now find it easier to measure with. For example, I find 5 foot 9 1/4 easier to remember than 176 cms for some reason.