It's a steel box!
https://youtu.be/kWiilCH1AO0?si=PxE3UuB9DE9sB0Hq&t=124
Norway's Rjukan seems to have implemented it better
The actuating system I developed can tilt pixels in a row at an angle proportional to their distance from the mesh center. This approach creates a "focus parabola" rather than a precise focal point—which would require actuators to tilt pixels according to an arctangent function relative to their center distance. Despite this limitation, I believe the design remains viable for my intended use, notwithstanding the significant incendiary risks involved.
While this approach might not be suitable for the scenario discussed in the article due to wind conditions and the need for a flat surface, it offers advantages over costly hydraulic systems. The mesh could be rolled up and transported in a bag, providing a potentially more portable alternative.
First reaction: why would a mirror cost this much?
> Eight metres wide and five tall, it reflects the sunlight for six hours a day, following the sun’s path in the sky thanks to a software programme that makes it rotate.
Also saw elsewhere that the reflectors are made of steel. So a giant, software-controlled, motorized structure, reflecting just the right amount of sunlight to a precise location, sitting out there in the elements...
Totally worth it, and what a cool project!
Relevant: https://en.wikipedia.org/wiki/Heliostat ("Aziz, Light!")