The paper aim is to define an original walking for a 2D biped with a trunk, two identical legs with knees and massless feet. This walking is composed of a ballistic single-support phase and a distributed in time double-support phase. The ballistic movement in single support is defined by solving a boundary value problem with initial and final biped configurations and velocity conditions. These conditions ensure that at the beginning of the single support the toe of the rear leg rises without touching the ground again and at the landing of the heel there is no impact. In the double-support phase, the orientation of the two feet and other generalized coordinates which are used to define the configuration of the biped, are chosen as Bezier functions of time. The torques and ground reaction forces resulting from this double-support phase are determined by solving for the biped the inverse dynamic problem. Statement of the problem The walking motion We design biped periodic walking, which consist of distributed in time single-and double-support phases. Ballistic single-support motion is designed. During this motion the torques in all joints are zeroes except the torque in the ankle-joint of the stance leg. The torque in the ankle-joint of the stance leg is applied in order to keep its foot in the equilibrium. During double-support motion the torques are applied in all the six joints; during this time both feet rotate: foot of the rear leg-around its toe, foot of the front leg-around its heel. To explain our statement of the problem more clearly, we show Fig. 1 with several stick-figures, which results from our numerical investigations. a) b) c) d) e)