robot = world:get_entity(4294967295)
layer = 1

local cnt = 0
function step(count)
    if robot:get_layer() ~= layer then
        --teleport back
        local x,y = robot:get_position()
        robot:warp(x, y, layer)
        if cnt >= 1 then
            --punish the player if he changes layer repeatedly
            local hp, max_hp = robot:get_hp()
            robot:damage(max_hp * 0.99)
        end
        cnt = cnt + 1
        --show warning message
        game:message("Don't change layers!")
    end
end
function init()
    --hide "Lua Script" object from the world
    local luaObject = world:get_entity(this:get_id())
    luaObject:hide()
    luaObject:warp(9999999,9999999,(layer + 1)%4)
end