Trebuchet and seals

I have been to visit Mr. Knight. Mr. Knight had a bicycle frame of a size I covet: I had a bicycle frame which was red; the visit effected their exchange. I arrived late in the evening, and when I awoke and looked out of the guest-room window I noticed that Mr. Knight had built a stone-removal machine. I enquired further over breakfast and established that outside Mr. Knight's front door were a number of fluorescent-painted stones which he needed to transfer two fields away by air; the machine proved effective, moving stones weighing between 8 ounces and 14 ounces; however the Knightlets proved mischievous and to Mr. Knight's dismay every time he opened his front door he found the self-same fluorescent stones had been replaced next to the aerial stone-moving machine, necessitating his immediate attention.

This is the stone-moving machine.

Here it is in action.

On my return Mr. Knight had business to attend to in Blenheim and on our way he directed me to stop at a small stream at Ohau Point, where we saw eighty tourists watching some moving objects near a waterfall.

Here are the tourists, the waterfall, and the moving objects.