This series of models develops a prototype for outdoor seating based on a Mobius.  An one-half twist and an one-and-one-half twist Mobius is investigated, as a band and a three-sided prism.  The goal was to determine if the concept of a nonconstant twist could introduce flat sections for seating and if the arrangement of flat and twisted sections can make the seating self-supporting.

The version presented here is one of more than twenty-four variations of flat and twist section angles, following both elliptical and circular paths.  This version alternates the three flat sections with three twist sections of 60 degrees each.  Each twist section goes through 180 degrees; a one-and-one-half twist Mobius.

Model 1 displays a smooth band and Model 2 a smooth prism.  Each are represented as continuous surfaces with no differentiation for the seating sections and nonseating sections except for the twisting.  Model 3 separates the band version into individual slats to differentiate the seating section from the twisting section by varying the dimension of the inner series of slats.  Model 4 separates the prism version into individual sections and varies the dimensions through the twisting sections.

The last two were named spiders because the individual sections reminded me of spider legs, appropriate for outdoor seating.  The twist also took on a more dangerous form, because of the projecting slats, adding to the spider concept.

A preliminary web site has been developed to display many of the variations investigated, see:

www.iit.edu/~krawczyk/spider  (active by October 1, 2003)

All of these models were developed with custom software within AutoCAD using the AutoLisp programming language.