"Wait!" he exclaimed.

"I show you sometings." He reached for my pencil, drew toward him a piece of paper, taking from his pocket meantime a bit of string.

Using the latter for a radius, he drew a circle on the piece of paper.
"Now look what I do!" he said, as I bent over curiously.

"See, I draw a straight line through the circle.

I divide it in half, so.