btain the same result?

A step farther? The visual picture, the mental image of the diagram to
obtain the same result? But how?

To one whose total orientation is through the use of physical tools (for
the material printed on the card diagram was the physical carrier of the
current) how to cause the current to follow the mental image of that
diagram? With voice and music bathing one's senses simply because one
thought of the diagram of a receiver? How?

He felt like the turkey come up against the obstruction of a fence too
low to justify the effort of flying over it. Instead of flying, he was
walking around and around, looking for an opening, walking in an endless
circle.

Circle?

Excitedly, he climbed down from the rock and headed for a patch of bare
sand at the river's edge.

In every framework of thought which man had ever devised, the circle was
prominent, vital. It played its part in every creed of every race, of
every time. It was as essential to the ancient arts of magic as to the
current methods of science. It played its part in the movement of
planets, the shape of stars, perhaps the essence of the total universe.

Man might be too didactic in requiring that awareness develop a physical
science comparable to his own, but surely awareness, whatever form it
took, would know the circle.

He sank down on his haunches beside the smooth sand, and with the tip of
his finger he quickly drew a circle.

The furrow, scratched in the sand, did not close or smooth out!

He sat back and waited. Nothing happened. It was almost as if the
invisible intelligence were saying, "All right. You are aware of a
circle. That was obvious to us from your artifacts. What else do you
know?"

He leaned forward, and as nearly as he could estimate, he dotted the
center of the circle with a finger, then scratched a radius to the
perimeter. It stayed. To one side he drew another line, approximating
the radius and in parenthesis he drew a small 2. Beside this he wrote
R^2. He drew an equals sign. He scratched the pi sign.

Then he drew another circle and with the palm of his hand he smoothed
all its interior. That should be plain enough. The symbols stayed. They
understood his mathematics, then. The equation seemed undisturbed, yet
there was something wrong with it. He had to look closely at the sand
before he saw what it was.

The = had changed to : !

Why had they changed the meaning by substituting "proportionate to" for
"