Instance API!

os.loadAPI("instance")

local w, h = term.getSize()
local running = true

objButton = instance.objectAdd(w/2, h/2, colors.orange)--Create object objButton

function objButton:create()--objButton creation code
  self.width=6
  self.heigth=3
  self.x=self.x-self.width/2
  self.y=self.y-self.heigth/2
  self.text="Random: "..tostring(math.random(1000))
  self.textLen=string.len(self.text)
  self.rxVel=math.random(-2, 2)
  self.ryVel=math.random(-2, 2)
end

function objButton:update()--objButton step code
  self.x=self.x+self.rxVel
  self.y=self.y+self.ryVel
  if(self.x<=1 or self.x>=w-self.width+1) then self.rxVel=-self.rxVel end
  if(self.y<=1 or self.y>=h-self.heigth+1) then self.ryVel=-self.ryVel end
end

function objButton:draw()--objButton draw code
  for xx=self.x, self.x+self.width do
   for yy=self.y, self.y+self.heigth do
	  paintutils.drawPixel(xx, yy, colors.orange)
	  term.setTextColor(colors.black)
	  term.setCursorPos((self.x+self.width/2)-self.textLen/2, (self.y+self.heigth/2))
	  term.write(self.text)
	end
  end
end

local function screenClear(col)
  term.setBackgroundColor(col)
  term.clear()
end

function main()
  screenClear(colors.white)
  local tmp=instance.create(objButton)
  local count=0
  instance.updateAll()
  while running do
	screenClear(colors.white)

	--After everything is done, update the instance's!
	instance.updateAll()
	count=count+1
	if(count>30) then
	  count=0
	  instance.create(objButton, math.random(w), math.random(h))
	  if(instance.exists(tmp)) then
		instance.destroy(tmp)
	  end
	end
	os.sleep(.1)
  end
end

main()