Code improvement

[droste89]

• [x] Transform phi into x (unclear)
• [x] Define a null dynamic inside the class creation
• [x] separate properties between modifiable and non modifiable.
• [x] Maybe add the angles to the initial call.
• [x] Check angle indices are different

[droste89]

Last solved in c7b38365b9848ea8685ca03cb8d4d82d5ce3e008