木 (Tree) vs 本 (Book/Origin) vs 休 (Rest) vs 体 (Body)
Adding a person (亻) or a root bar (一) to a tree (木) creates four of the most common kanji in Japanese.
5-Second Radical Distinction Rule: 木 (Tree) • 本 (bar at the roots of the tree = Origin/Book) • 休 (person 亻 leaning against a tree 木 = Rest) • 体 (person 亻 + root/foundation 本 = Body).