构

Left tree radical — a pictograph of a tree with roots and branches, here in its compressed left-side form. The indexing element. Anchors 构 in the wood-construction family with 桥 (bridge), 柱 (pillar), 楼 (multi-storey building), 架 (framework). Buildings, frames, and structures were historically made of wood; the radical signals that this character names making or fitting things together.

Right 勾 supplies the sound — gōu drifting to gòu through tone shift. Helpfully, 勾 means 'to hook, to link' — exactly the action behind constructing something: hooking pieces together. The phonetic doubles as a semantic clue. Replaces the traditional 構 which used the more elaborate 冓 (interlocking) on the right; the simplification keeps the same meaning with a simpler graph.