Each year, I try to create an activity for visitors to enjoy building at the SF Sunday Streets events. This year I drew inspiration from tensegrity structures like this one that I found online.
I designed a smaller version of the structure that can be cut on laser cutter using 1/8 inch plywood. My goal was to create something that could be assembled without glue and that I could be made in bulk without too much hassle.
With this design, four kits can be cut from a piece of 12″ by 12″ stock.
To assemble the kits, five lengths of string are used to connect the center arms and the four corners of two platforms. Strings are knoted to the corners of the bottom platform and a friction cleat is used to allow the strings to be easily connected and disconnected to the top platform. The allows you to experiment with different length of string and switch easily between the more captivating two anchor configuration, and the more stable four anchor configuration.
I also created a larger version of the structure to use in discussion about how it works. Each string in the larger version is connected via magnetic anchors to make it easy to remove any of the strings and discuss the role they play in holding up the top piece.
All in all, the kit was well received and led to many great discussions with folks of all ages.
At first glance the structure is a bit mysterious, but when you get a chance to play with it, it becomes fairly intuitive how it works.