This prototype clock by Boaz Cohen and Sayaka Yamamoto tells the time in a straight line by replacing the hands with a pivoting shell-like structure.

Curators Isabelle Daëron and Fabien Petiot commissioned the duo that make up BCXSY to "create an object with a relation to circular movement" for an exhibition of mechanical animated objects as part of the Designers’ Days event in Paris. The result was Linear Cycle, a prototype for a linear clock.

The clock comprises a rotating shell-shaped form which spirals outwards, and a vertical axis marked with 12 lines, one for each hour. As the shell rotates, the part crossing the axis reaches a different hour mark.

"The shell is a simple representation of a circle divided in 12, one for each hour, and then each section-line has a different length, also in 12 increments. We drew those lines from the centre, and only then connected them, happily discovering the 'shell' form. It was a classic case of form follows function," said the designers.

The prototype was made by hand from heavy-duty light grey cardboard, commonly used for model-making. The shell-shaped dial is made from a plastic, and the clock mechanism is particularly strong to carry its weight.

The monochromatic colour palette was chosen to highlight the most important part of the clock – the rotating dial and the hours.

"We've always been drawn to common and simple objects. Watching a clock has sort of a meditative aspect – so maybe it was a certain state of mind, with the brief in the back of our heads, that resulted in a quick and spontaneous sketch." said the designers.

"It might be a bit of a cliché, but sometimes you find something when you’re not really looking for it."

The Linear Cycle was on display as part of the Roues Libres exhibition during Designers’ Days in Paris in a bid to find a suitable manufacturer.