height of lego studs
Sometimes its easier to see your brick's shape if you turn on the edges, View->Show Edges. brick() takes a ton of different parameters. The normal ones are length, width and height, in Lego studs for length/width and plates for height. 1,1,3 creates a normal 1x1x1 brick. brick() is most useful for making more interesting shapes, such as when you need to plug things together in strange ways or parts are misaligned by a 1/2 brick and so on.