[mfost]

It's just a matter of working with base elements that are divisible by 3 and 4 really.

So instead of buying 100cm planks, buy 120cm planks?

[philwelch]

And eventually you’re going to want a name for your 120cm unit. But that’s not allowed in metric because any named unit has to be base 10.

[olddustytrail]

It has a name. It's the plank length.