You don’t have to speak French in order to Notice and Wonder about this bit of architectural design! Leave a comment to tell us your thoughts (French is optional)!

## Voulez Vous des Voussoirs?

A voussoir is a trapezoidal piece of stone often used to build arches.

Hi there, great site you have. just a question in relation to voussoirs. What is the formula in constructing a semi circle arch with bricks given a common brick size 230mm length x 115mm width x 75mm height. Arch span is 530mm. Specifically how many bricks you will need and what angle(or how much) would you need to cut the bricks into voussoirs to fit a arch.

Thanks in advance

Hi, Tina. I wonder if any of the thinking in our other blog post about voussoirs, “What Do You See in the Voussoirs?“, would help you in trying to figure this out. It’s an interesting twist on our problem, since here you have the rectangular boxes and want to find the angle, whereas before we knew the angle and wanted to figure out how many blocks!