A first object is anchored in a second object. The first object has a material with thermoplastic properties, and the second material has a material that is solid and is penetrable by the first material when in a liquefied state. The second object has an insertion face with an opening having a mouth in the insertion face, and the first object has an insert portion that for anchoring is placed in the opening or about the mouth thereof. For anchoring, energy suitable for liquefaction of the first material impinges in an amount and for a time sufficient for at least partial liquefaction of the first material and interpenetration of the first and second materials. The second object, around the opening, has an anisotropic strength with respect to forces perpendicular to the opening axis.