2

os.loadAPI("GUI")
b={}
f={}
local p1 = GUI.NewPanel(21,4)
for i=1,16 do
  b[i]=GUI.NewButton(nil,1,1,3,3,tostring(i),f[i])
  f[i]=function(s)
  s=rednet.send(xxxx,i)
  end
  p1:addCHILD({b[i]})
  i=i+1
end
for i=5,8 do
  b[i].x=6
  i=i+1
end
for i=9,12 do
  b[i].x=11
  i=i+1
end
for i=13,16 do
  b[i].x=16
  i=i+1
end
for i=2,14,4 do
  b[i].y=5
end
for i=3,15,4 do
  b[i].y=9
end
for i=4,16,4 do
  b[i].y=13
end
GUI.MainPanel:addCHILD({p1})
GUI.MainPanel:draw()