I was reading an old science fiction novel (The Complete Venus Equilateral by George O. Smith 1945)
The protagonists are trying to invent a matter transmitter, and using a glass cube as a test item.
As I read about their difficulties, it reminded me of the various ways a 3D print can fail, and the advice people give to solve various printing problems:
“I presume that you shipped me one of the cubes?”
“Right.”
“Well, what we got at this end would positively scare the right arm off of a surrealist sculptor.”
“Hang on to it. I’ll be right up.”
“Hang on to it?” laughed Don. “I’m afraid to touch it.”
It was three miles from one end of Venus Equilateral to the other and Walt made it in six minutes from the time he stepped into the little runway car to the time he came into the north-end laboratory and looked over Channing’s shoulder at the–thing–that stood on the table.
“Urn,” he said. “Sort of distorted, isn’t it?”
“Quite,” said Don. “This is glass. It was once a three-inch cube of precision, polish, and beauty. It is now a combination of a circular stairway with round corners and a sort of accordion pleat. Hell’s bells!”
“Be not discouraged,” gurgled Walt. “No matter what it looks like, we did transmit matter.”
Walt, we did accomplish something. It wasn’t too good. Now let’s figure out why this thing seems to have been run over with a fourth dimensional caterpillar-tread truck."
“Well, I can hazard a guess. The synchronizing circuits were not clamped perfectly. That gives the accordion-pleat effect. The starting of the trace was not made at the same place each time due to slippage. Well have to beef up the synchronization impulse. The circular-staircase effect was probably due to phase distortion.”
“Could be,” said Don. “That means we have to beef up the transmission band so it’ll carry a higher frequency.”
“A lower impedance with corrective elements?” “Might work. Those will have to be matched closely. We’re not transmitting on a line, you know. It’s sheer transmission-tube stuff from here to there. Well, gang, we’ve had our fun. Now let’s widen the transmission band and beef up the sync. Then we’ll try number two.”
Number two was tried the following afternoon. Again, everybody stood around and watched over Don’s shoulder as he removed the cube from the cabinet.
“Nice,” he said, doing a little war dance.
Franks came in puffing, took the cube from Don’s fingers, and inspected it. “Not too bad,” he said.
“Perfect.”
“Not by a jug full. The index of refraction is higher at this edge than at the other. See?” Walt held the cube before a newspaper and they squinted through the glass block.
“Seems to be. Now why?”
“Second harmonic distortion, if present, would tend to thin out one side and thicken up the other side. A sine-wave transmission would result in even thickness, but if second harmonic distortion is present, the broad loops at the top create a condition where the average from zero to top is higher than the average from zero to the other peak. Follow?”
“That would indicate that the distortion was coming in at this end. If both were even, they would cancel.”
“Right. Your scanning at one end is regular–at the other end it is irregular, resulting in non-homogeneity.”
“The corners aren’t sharp,” objected Arden.
“That’s an easy one. The wavefront isn’t sharp either. Instead of clipping sharply at the end of the trace, the signal tapers off. That means higher-frequency response is needed.”