Pritzker prize-winning architect Álvaro Siza has designed a square watch, the Lebond Siza, which is based on one of his earliest projects and will be his "Sunday watch".

The architect referenced his design for the Leça swimming pool complex in Portugal, which he created in 1966 at the age of 28, when creating the watch.

Its angular case was informed by the square shape of the main swimming pool, while the watch hands nod to the minimalist restroom signs found in the leisure complex.

The aim behind creating a square watch was to design something different, the 89-year-old architect said.

"There already exist many beautiful round watches," Siza said. "I want to create something different."

"It is an elegant and sophisticated watch," he added. "It will be my Sunday watch."

Created for Lebond Watches, a brand that specialises in architect-designed watches, the Lebond Siza is made from a high-strength titanium alloy.

According to the brand, Siza chose the material for its "lightness and beautiful micro-sanded matte finish".

The was has a black rubber strap with a deployment clasp and a black watch face that features the numbers 3, 6, 9 and 12 in a minimalist design.

The watch case has an open back that showcases the mechanical movement of the watch, which has been decorated with Siza's signature.

"The Lebond Siza watch is an exceptional timepiece that seamlessly blends style and functionality, showcasing the architect's talent for creating minimalist and elegant designs," Lebond Watches said.

It is the most recent watch design by Siza, who also created the Cauny x Siza collection for Swiss brand Cauny, including "a watch that would look like a watch".

Siza, who won the prestigious Pritzker Architecture Prize in 1992, has also recently designed a concrete art pavilion in South Korea and a limestone-clad skyscraper in Manhattan.

The photography is by Fernando Guerra and sketches are by Siza.