function onThink()
    local square = {
        frompos = {x = 1252, y = 1007, z = 5},
        topos = {x = 1261, y = 1013, z = 5},
        exitpos = {x = 1253, y = 1010, z = 6}
    }

    local players = 0
    local playerNoMapa
    for a = square.frompos.x, square.topos.x do
        for b = square.frompos.y, square.topos.y do
            local pos = { x = a, y = b, z = 5, stackpos = 255 }
            local player = getTopCreature(pos).uid
            if (isPlayer(player)) then
                playerNoMapa = player
                players = players + 1
            end
        end
    end
    if (players == 1) then
        -- faz a magica aqui
    end
    return true
end