Flexible rulers trace existing curves or create new ones with equal ease. Westcott's Flexicurve holds whatever shape you bend it into, staying put when pressed against paper while you draw along its elevated edge. The raised profile keeps your pen or pencil tip precisely guided without ink bleeding underneath, critical when inking curved architectural elements or technical illustrations where precision matters more than speed.

Bend it to match organic forms you're referencing, then flip and trace the mirror image for symmetrical designs. The malleable core maintains its shape through repeated adjustments, letting you refine curves incrementally until they're exactly right. Fashion designers use these for pattern drafting; illustrators rely on them for vehicle contours and product renderings; architects reach for them when templates don't quite match the curve they need.

Unlike French curves that force you to find the right template, this tool becomes whatever curve your work demands. The shape-memory construction means it won't spring back or shift while you're working, and it lies flat enough that gentle pressure keeps it stable without requiring both hands. Simple, adaptable, and surprisingly indispensable once you understand what it can do.