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xkcd #3244: Pullback Drive
(imgs.xkcd.com)
Title text:
"How does the spring not run out almost immediately?" "We pull it back REALLY far."
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3244/
Or get free delivery of dumbbells and other heavy stuff to your house and send them back from your workplace.