Equations for the vectors

• (a₁, a₂) = (a₂, a₃) = ... = (a₆, a₇) = (a₇, a₁) = c

• (a₁, a₁) = (a₂, a₂) = ... = (a₇, a₇) = 1

• a₁ + a₂ + ... + a₇ = 0

For c = 0 :	equations for the configuration space of a robot.
For c = 1/3 :	equations for the configurationspace of a molecule.