Abstract: A lace-tensioning device which is a rigid cylindrical body (64) with two passages (58, 60) aligned parallel to the cylindrical axis and a handle element (62) projecting from the body (64) perpendicular to the cylindrical axis and functioning as a lever. The device is used in a laced closure by modifying the lacing pattern from the standard alternating pattern at one of the pairs of guide elements (68, 70) of the closure and threading the lace (75) through both passages (58, 60) of the tensioning device. A segment of lace (76) from one side (82) of the closure goes through one passage (60) in the device and then back to the same side (82) of the closure from which it came. A segment of lace (78) from the opposing side (84) of the closure goes through the other passage (58) in the tensioning device and back to the same opposing side (84) from which it came. The lace (75) is otherwise laced conventionally and its ends are tied together in a secure knot.

Abstract: The invention comprises a continuous surface made from jigsaw puzzle pieces, wherein the three or more pieces whose corners share a common point when assembled, have corner angles whose sum is less than 360 degrees with the common point as vertex of said corner angles. The present invention makes it possible to work on jigsaw puzzles which, when assembled and during assembly, form continuously curving polyhedral surfaces, and to provide a jigsaw puzzle whose pieces assemble edge to edge into a self-supporting curved surface which is a closed multifaceted polyhedron whose appearance is substantially spherical.