So the base, so this area right over here, if I was transparent, I could continue to draw it down here. But this right over here, that material costs $10 per square meter. Let me label that. $10 per square meter. And then they say material for the sides costs $6 per square meter. So the material over here costs $6 per meter squared. So let's see if we can come up with a value or how much this box would cost to make as a function of x.