The commission was advertised in April 2005, inviting sketch ideas with the theme "the movement of air".  Following a site visit of the old Fläkt-Woods factory, the following proposals were submitted:

  Towers

Dandelion

Tunnels

Six artists were shortlisted from the initial stage, and after feedback from the panel, two artists were selected to attend interview, each with a single developed proposal.

The 'Towers' idea was refined to the current design, and additional 'lead-in' artworks were proposed to lead up to the main sculpture: 

Final Design

Lead-In artworks

Landscaping

In the final arrangement, these satellite artworks were dropped due to the new location.

The commission was awarded on the strength of this design.  The considerable delay between the commission being awarded and commencement of works was due to the sculpture being scheduled with the third phase of housing on site.

When detailed design was begun, structural analysis of the design (for wind loading, stability, etc.) required a 3D wireframe CAD version to be made:

This was also very useful in fabricating the sculpture, to help set out the angle of the towers.  

Using the CAD design, a laser-cut acrylic scale model was made to help plan the spiral surface.

Vortices (maquette), acrylic sheet, aluminium wire, 40 x 45 x 50 cm