Image acquired but not used to illustrate lecture text for 'Representation in building' by Steven Groak, held at the RSA, 18/2/1998. Photograph supplied by Steven Groak and Ove Arup and Partners

Image acquired but not used to illustrate lecture text for 'Representation in building' by Steven Groak, held at the RSA, 18/2/1998. Photograph supplied by Steven Groak and Ove Arup and Partners

Image acquired but not used to illustrate lecture text for 'Representation in building' by Steven Groak, held at the RSA, 18/2/1998. Photograph supplied by Steven Groak and Ove Arup and Partners

Image acquired but not used to illustrate lecture text for 'Representation in building' by Steven Groak, held at the RSA, 18/2/1998. Photograph supplied by Steven Groak and Ove Arup and Partners

Image used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998

Image acquired but not used to illustrate lecture text for 'Straight lines and great circles: reweaving the local' by Susan Clifford, held at the RSA, 4/3/1998