A pair of surprises: a celebrated spire made out of cardboard not stone, and a casual slide sheathed in springbox hide. Both surprising in their use of material.

The architectural part of this pair appears as part of the 2014 Agora Biennale in Bordeaux, France, an event that explores the built potential of the port city. This year’s theme, public space, investigates political, cultural and social possibilities; public space as not only site of political protest, but also the Greek Agora, a gathering space for open discussion and sharing. “Public space is a precious place where we can transform the everyday,” said 2014 Agora curator Youssef Tohmé, an architect and city planner. “Because it is a space where anything is possible, it has the power to bring us out of ourselves. Its value depends on its potential for experience and adventure.”

As part of this week’s Agora adventure, Marseille-based artist Olivier Grossetête presents Les Bâtisses Soeurs (Sister Buildings), monumental yet ephemeral constructions in cardboard, at once autonomous and referential to the architecture surrounding his installations. Working with a community crew, Grossetête transformed 4,500 cartons, or 5 tons of packaging, into three life-size replicas of important Bordeaux buildings. As the Agora finale, the cardboard trio will be demonstratively demolished a week from today.

On the sartorial side of surprise, a sandal handcrafted in South Africa by Brother Vellies, a line founded by fashion insider Aurora James with the goal of introducing the world to traditional African footwear while also supporting artisanal jobs in the region. Every element of the sandal is sustainable: the springbox is sourced from small farmers as a byproduct of the edible food industry, and scraps from adult designs are used in Brother Vellies’ kiddo line; the cotton denim is hand-dyed with plant-based indigo; and the leather sole is kudu, a species of antelope prone to overpopulation and thus managed by government mandate. Like Grossetête’s sister structures, Brother Vellies’ shoes signal a fresh approach to traditional construction. Twins in surprisingly sustainable cool.