Oscillating weight with variable geometry for a timepiece mechanism

A timepiece comprising:

• an oscillating weight with variable geometry for a timepiece mechanism for a watch worn by a user, comprising:
• a first part,
• a second part,
• a first axis of rotation common to the first part and to the second part, at least one of the first part and the second part being arranged to be able to oscillate about said first axis of rotation,
• a first sun gear, coaxial with the first part and the second part and linked to the first part;
• a first planetary wheel, comprising a second axis of rotation, said first planetary wheel arranged both to revolve about the second axis of rotation and to revolve about said first sun gear,
• a second sun gear, linked to the second part and coaxial with the first part, the second part and the first sun gear,
• a second planetary wheel, comprising a third axis of rotation, said second planetary wheel being arranged both to revolve about the third axis of rotation and to revolve about said second sun gear,
• a frame having an axis of rotation and comprising a end bearing said second or third axis of rotation of said first and second planetary wheels, and a toothing, and
• a control wheel adapted to mesh with said toothing, so as to drive said frame about its axis of rotation, resulting in the rotation of said first and second planetary wheels about their respective axis of rotation and an angular displacement of said first part with regard to said second part.