may be formed integrally with pivoting members 30 40 such as by insert molding two shot molding selection of high friction geometry or other formation methods fig1 shows anti slip member 80 formed integrally with pivoting member 30 via the design of a texture on pivoting member 30 fig1 shows a pad member 100 between the unstable platform 10 and the surface 50 the pad member 100 is capable of acting as at least one of a bumper member and an anti slip member according to one preferred embodiment the pad member 100 is provided as a separate component from the unstable platform 10 and the pad member 100 can act as both a bumper member and an anti slip member those knowledgeable in the art will recognize that suitable materials for the pad member 100 include but are not limited to natural rubber latex free rubber silicone epdm viton foam and other materials or constructions with at least one of force absorbing properties and high coefficients of friction now referring to fig1 13 a and 13 b a preferred embodiment is shown where the planar member is rectangular having two long edges 21 and two short edges 22 the first 30 and the second pivoting members 40 have a half disk shape the planar member has an anti slipping member 80 and a cavity 90 referring now to fig1 a and b another preferred embodiment is shown where the pivoting member is formed of a tube bent to a half circle the hollow middle of the half circle forms a cavity 90 that can.