ladder paradox
thought experiment in special relativity: a ladder parallel to the ground moves horizontally; due to length contraction it fits inside a garage; but from the ladder's frame, the garage will be contracted to be smaller and cannot contain the ladder
en-GB/ˈlædə ˈpæɹədɒks/
en-US/ˈlædɚ ˈpæɹəˌdɑks/