Abstract: An abrasive article and methods of making and using the same are disclosed. The abrasive article includes a plurality of features on a backing. The features have a base and a body. The body is defined by sidewalls having parabolic sections. In some embodiments, the sidewalls are defined by a series of inner-connected lines segments approximating a parabolic section.

Abstract: Jigsaw puzzles for use by young children to practice elementary arithmetic. Each puzzle is circular and includes a center piece, four middle ring question pieces, and twelve outer ring answer pieces. One side of each puzzle contains the arithmetic question and answer pieces and the other side forms a picture when the question and answer pieces are put together correctly. A transparent tray is used for assembling the pieces of the puzzle. A transparent cover is adapted to be snapped into place over the tray and allow the container to be turned over to view the picture side to determine if the picture is either (1) correct, which means that all of the arithmetic questions have been answered correctly or (2) incorrect, which means that some or all of the arithmetic questions have not been answered correctly.