You probably mean the pool quadruples in size, meaning it doubles in length.
Re:Deepest infrared image of universe
by thehappypm on Tuesday July 12, 2022 @01:32PM
(#32073245)
No, I mean doubles across all axes. 1 unit cubed becomes 2 units cubed.
Your friend right next to you who was one foot away is now two feet. The absolute distance just grew by 1 foot, a rate of 1 foot/second.
Your friend across the pool who was 10 feet is now 20 feet away. Absolute distance just grew by 10 feet, or a rate of 10 ft/sec.