This is a one-week, full-scale furniture design project with two people requiring the use of CNC technology to create an ergonomic chair made of plywood. This one-week project involved a two-person team designing a plywood ergonomic chair using CNC technology. Inspired by Gerrit Rietveld's Red Blue Chair, our design features vertical and horizontal elements for a geometric rhythm. In addition, we use grasshopper to draw Voronoi diagram ( a type of geometric figure) on the tall chair back with grasshopper to emphasize the rhythm.