carpenter's square

She’s wrapped tightly in a white bed-sheet and has a carpenter’s square on her head.

Something that looks just like a carpenter’s square.

Some are obvious, such as the armillary sphere and quadrant, an architect’s plumb bob and carpenter’s square, a compass, and a pair of dividers.

He held a carpenter’s square, representing his vocation as a carpenter.

This was the time of Theodorus, the master engineer of the age, credited among the Greeks with the invention of the key, the ruler, the carpenter’s square, the level, the lathe, bronze casting and central heating.