Title: Swiss Roll
Source: Borg and Groenen (2005)
Description: Data generated on the surface of a Swiss roll. The points
lie on the surface of a 2D plane that is rolled. The coordinates are
for row i are given by:
x_i = .5*sin(4*pi*v_i)
y_i = u_i-.5
z_i = .5*v_i*cos(4*pi*v_i)
for uniformly distributed v_i and u_i between zero and one.