Vibrating objects exchange energy based on their physical shape rather than how fast they are moving.

Standard physics says that two things with similar frequencies will naturally resonate and swap energy. Real-space imaging of mechanical resonators shows that spatial symmetry is actually the dominant gatekeeper. Energy is routed between modes only if their shapes match specific rules, regardless of their frequency. This challenges the basic intuition used to design everything from bridges to electronics. Understanding this shape-first rule allows for much better control over how heat and sound move through materials.