Asseyez is a stool that remembers being sat upon.

It has a mechanical counter that increments when someone sits on the top seat. The cushion is made of thermochromic leather that changes color based on body heat.

The main challenge in designing Asseyez was to create a smooth system with a spring and telescoping tubes so that the counter would be triggered correctly, even when a person sits on the edge of the seat.

Designed and manufactured in the Product Realization Lab at Stanford.


Steel, maple, plastic, thermochromic leather


Welding, turning, milling, sewing

Before someone sits down, the seat is a consistent orange: When someone has recently sat on Asseyez, their heat pattern is momentarily visible on the cushion and the counter is incremented:

Design Process


The idea for Asseyez comes from two questions that come to mind when I think about the lifetime of a chair. When I see a chair, I think “How many people have ever sat on this chair?” and “When was the last time someone sat on this chair?” I decided to build a stool that could answer these questions.

Initial designs varied between 3 and 4 leg designs with the spring and counter sandwiched in various ways. The design evolved to a single tube with a spring at the base which would be compressed by a smaller telescoping tube.

The mechanical nature of the counter was important to me as I wanted the counting interaction be entirely analog.


Early wood prototype:

Testing the thermochromic properties of the seat with the warmth of my face:


Welding the metal pipe to sheet metal: Turning the Delrin spacers: Woodworking, routing the seats for the counter pocket:


Going through the entire product realization process from an idea to a real physical stool has been immensely rewarding. It's empowering to know that I can make objects come to life.

For now, Asseyez sits in my room, quietly waiting for people to take a seat.