Among other things, uterine lavage is performed to withdraw at least 50% of in vivo fertilized preimplantation embryos produced after superovulation of a woman and artificial insemination using sperm of her sexual partner. Expansions can be kept track of so that reductions after refactoring can be confined to altered portions of the program source code. A query model including static and temporal components is then determined for the object. When the sliding operation of the movable member is finished, a resilient force of the resilient member stretched in the certain direction forces the movable member to return automatically to the initial position. Various embodiments are shown wherein the clip may be attached to the head of the hammer in various ways.