変形

1. Origins, structure, and basic meaning

• Structure: 変形 is read as へんけい and functions as a noun or with する for a physical object or geometric form changing shape.
• Basic usage: Distinguish 蓋が変形する for a shape changing and 別の形に変形させる for causing that change.

2. Common pitfalls and similar expressions

• Cause and agency
  • Heat leaves the lid as the subject that deforms, while folding paper makes an actor deliberately transform the shape.
• Scope of the change
  • The word here concerns form or structure, not merely a change in content, rules, or opinion.