In this obelisk the tetrahedra are joined face to face to create a twisted column with triangular faces. The edges of this arrangement follow helical lines, it is referred to as a tetrahelix. Note, it forms right-handed helices like in the structure of DNA. The tetrahelix space frame is a beautiful geodesic structure expressing life and growth, which is most appropriate for the support of plants.
Sixteen of these 21st century obelisks were erected in a double rose border over 100 metres long at the RHS Garden Harlow Carr. This project was first shown on the BBC Gardener’s World Roadshow on 09.07.05 and again in Gardener’s World on 02.09.05. A similar photo was included in the RHS poster in 2006 to excite garden lovers to join the RHS.