outline

local args = { ... }  --row and col

--Set variables
local length = 10
local height = 3
local row  = args[1] or 1
local col = args[2] or 1

--Set monitor properties
mon = peripheral.wrap("monitor_1")
mon.setTextScale(0.5)

--Calculate position and offset
local posX = (row-1) * length + 1
local posY = (col-1) * height + 1
local offsetX = posX + length - 1

--Outline of button
mon.setBackgroundColor(colors.white)
mon.setCursorPos(posX,posY)
mon.write(string.rep(" ", length))

mon.setCursorPos(posX,posY+1)
mon.write(" ")
mon.setCursorPos(offsetX,posY+1)
mon.write(" ")

mon.setCursorPos(posX,posY+2)
mon.write(string.rep(" ", length))