Shades of Brunelleschi is a minimal chair created by Tokyo-based designer Toshiki Omatsu. Chairs with an arc for the seating surface are rarely produced. It is a shape that is avoided for various reasons such as sitting comfort. However, when you sit in an arc, you feels more wrapped up than a flat seat, which is surprisingly comfortable. To achieve a feeling of floating, one has to produce the chair as thin as possible. While easy to make out of steel, the chair itself would be very heavy. By using aluminum, the weight would only be one-third that of steel. However, since aluminum is a softer material than steel, it cannot be structurally established. It was a surprisingly difficult task to measure the thickness without losing structural integrity. As a result of repeating this trial and error for more than half a year, the studio completed a chair that can withstand a weight of up to 100 kg with 4 mm thick aluminum by devising the method of joining and welding between members. The thinness of the aluminum can be seen by looking at the chair from the front.