-- pad out one node fully, and all other nodes just enough to keep them from overlapping.
-- We don't want cascading movements to get too chaotic.
prepare_to_move = function(target)
		def.hs.x = def.w/2
		def.hs.y = def.h/2 + 30
		if def == target then
			def.hs.x = def.hs.x + 50
			def.hs.y = def.hs.y + math.max(30, math.min(def.h/3, 200))
		end
		def.pos.x = def.x + def.hs.x
		def.pos.y = def.y + def.hs.y
	for _,def in pairs(Definitions) do
		assert(def.w)
		assert(def.h)
		if def.pos == nil then def.pos = {} end
		if def.hs == nil then def.hs = {} end

		prepare_to_move(node)