It looks like a castle keep with its crenellated top, just the place from which to pour boiling oil down on the heads of any knaves and varlets trying to capture Loy Park. But there has not been an attack of knaves and varlets in quite a while, so what is up with Grayson County’s medieval monument? The stone tower in the park stands on a small hill just off the road to the fairgrounds. It is separated from the lake by a cluster of oak and pecan trees.