The Object Pool pattern

Back at the factory, Phoebe has made progress on the robotics. She has developed a mobile robotic arm to handle the welding during the manufacturing process. She was hoping to build 30 of these arms to allow for maximum factory output, but her father’s credit card mysteriously stopped working. This puzzled Phoebe. Could her sister have told on her, leading her father to block the card from further purchases? “She wouldn’t do that!” Phoebe thought, but as soon as she said it, she knew that’s exactly what had happened. She considered calling her sister out on it but decided to focus on her father’s words:

“A good engineer is someone who makes the best product possible given constraints of time, materials, people, and budget with a minimum of complaining.”

The last part is the hardest. Most engineers complain, “If I’d gotten the budget, I’d asked for…” or “If...