Drawing Combinations
case .Beside(let l, let r):
let (lFrame, rFrame) = splitHorizontal(bounds,
l.size/diagram.size)
draw(context, lFrame, l)
draw(context, rFrame, r)
case .Below(let t, let b):
let (lFrame, rFrame) = splitVertical(bounds,
b.size/diagram.size)
draw(context, lFrame, b)
draw(context, rFrame, t)