We’re all pretty familiar with straight lines and right angles. When you have to cut out an irregular shape, however, the hapless carpenter is often forced to resort to guesswork, astrology, or simple trial and error.

This tool makes tracing or duplicating a curved outline as easy as falling out of a tree.

The idea is simply to press it against the object you wish to duplicate – the pins will conform to its shape. You can then use a pencil to transfer the curve to a piece of wood, linoleum, baseboard, drywall, or whatever you happen to be working with.

This coping gauge is 10 inches (25 centimeters) long; two can be connected to profile larger objects.

You’ll need a fairly delicate touch and avoid jostling it once you have the correct shape. This is because there’s no way to lock the pins in place.

They’re pretty stiff, though: you may even scratch or damage very delicate objects if you’re not careful.

Serious contractors might prefer a contour gauge made of metal; this one is plastic. It should last the average DIY’er for quite a while, but getting bounced around in a cluttered toolbox will probably cause some of the pins to snap.