Exman rolled backward! Bud gave a whoop of delight.
Tom signaled: Move forward. Obediently Exman rolled toward him.
Stop. Exman stopped.
"Hey, how about that?" Bud exclaimed happily. "It really savvies those electronic brain impulses!"
"And minds them—which is equally important," Tom added.
A moment later the brain energy seemed to become impatient. It spurted off in its wheeled container toward a laboratory workbench.
Crash! A rack of test tubes went sailing to the floor with an explosion of tinkling glass.
Stop! Tom signaled frantically. Again Exman obeyed the order.
"It's like a mischievous kid," Bud said.
Almost as if in defiance, Exman scooted off in another direction. Then it stopped abruptly and swiveled around, one of its antenna arms knocking a Bunsen burner to the floor as it did so.