Model of transformation (2)

Etched on the copper plate at bottom left of the model is an explanation of it: “The Wriggling Steel Rod – the original intention was to transform the triangular-section rod on the upper far right of the model into the shape on the near right.  Or, more precisely, as much of the surface of the rod into as similar a configuration to that on the near right as possible. What has been achieved is the transformation of that portion of the rod’s surface shown on the lower far right, into the configuration above.  The reason for the fact that less than half of the rod’s surface has been transformed (lower far right) is that only two planes passing through the centre of the sphere can be simultaneously transformed and perceived, using intersecting circles – one for each plane – of possible positions of the eye.  If this appears a long way from the original intention, it must be argued that the above shape resembles the one on the near right considerably more than either of them resemble the triangular-section steel rod”.