Abstract: A building block includes three serially connected square frames, each of which has an outer frame portion and an inner cross-shaped located within the outer frame to divide a space enclosed in each square frame into four equal parts. The cross-shaped rib portion has a thickness at least twice as large as that of the outer frame portion. All the three square frames have two diagonally opposite cavities provided thereon, while one of the three square frames further has two connecting protrusions diagonally located at two sides of the two cavities, so that multiple pieces of the building blocks could be assembled together in different manners to form changeful shapes via engagement of the cavities with corresponding connecting protrusions.

Abstract: A building block includes two perpendicularly connected square frames, and a hypotenuse frame extended between outer edges of the two square frames. Each of the square and hypotenuse frames has an outer frame portion and an inner cross-shaped rib portion having a thickness twice as large as that of the outer frame portion. The cross-shaped rib portion divides a space enclosed in each frame into four equal divisions, which are four cavities on one of the two square frames; two diagonally opposite round connecting posts and two diagonally opposite cavities on the other square frame; and two diagonally opposite connecting protrusions and two diagonally opposite rectangular cavities on the hypotenuse frame, so that a plurality of the building blocks could be assembled together in different manners to form changeful shapes via engagement of the cavities with corresponding connecting posts or protrusions.

Abstract: A building block includes a partially hollow cubic body, each side of which includes a square frame portion having a predetermined thickness, and a cross-shaped rib portion having a thickness twice as large as the thickness of the frame portion. The cross-shaped rib portions cooperate to divide a space behind each frame portion into four squared cavities. At least one side of the cubic body is provided at two diagonally opposite cavities with two centered round connecting posts projected from that side by a predetermined distance, and each of the round connecting posts has an outer diameter equal to a length of each side of the squared cavity. Any two laterally or diagonally disposed building blocks could be firmly connected to each other by inserting the round connecting posts of a third building block into two diagonally opposite cavities separately on the two laterally or diagonally disposed building blocks.

Abstract: An instructive clock with removable numerating strips mainly includes a clock having time scales provided on a face thereof to show a time point indicated by hour, minute, and second hands of the clock; and at least one numerating strip in the form of an elongated strip for annularly fitting on the clock. The at least one numerating strip is provided on a front side with time marks corresponding to the time scales provided on the clock, and at two ends with corresponding female and male connectors that could be fitly engaged with each other.

Abstract: A building block includes a cube, five of six sides of which is respectively provided with four through holes while the sixth side is diagonally symmetrically provided with two projections and two through holes. The building blocks may be connected to one another in many different manners to create various shapes, and could be conveniently stored in a closed container and produced at reduced cost.

Abstract: The present invention discloses an improvement structure of a game circle. The game circle mainly includes four same arcs, and axis set on the game circle, the axis is formed by a fixing element fixed into a through hole, and the fixing element is formed as one at one end of the arc, and the through hole is at another end of the arc; a recess set at the center of the fixed element, and the fixing element with flexibility when fixing something fixes arc together. By the way, the benefits of replacing rapidly and reducing cost can be reached.

Abstract: An improvement structure of a ruler, comprising: two rulers; an axis, composed of a hollow axis and a fixed axis, said hollow axis and said fixed axis being formed as one respectively to the ends of said rulers, said hollow axis being composed of an upper ring and an lower ring to combine said two rulers as one. Therefore, an improvement structure of the ruler of fewer elements, low cost and replacing rapidly can be obtained.

Abstract: A teach-aiding weight set includes a white, a red, a light green, a purple, a yellow, a green, a black, a brown, a blue, and an orange weight. Each of the weights is provided with spaced shallow grooves to show a plurality of equal sections corresponding to a specific weight thereof. The specific color, weight, and shallow-groove-divided sections of each of the weights help small children to learn primary mathematical concepts, particularly the concept of weight.

Abstract: A carton serving as a package for a Transformable Pyramid, which is a built-up type intellectual teaching aid, is produced from a cardboard divided into two groups of four right triangular faces for folding into first and second pyramidal parts, respectively. The first and the second pyramidal parts in the folded state provide two open-bottomed four-face pyramidal bodies connected and closable to each other to fitly enclose the Transformable Pyramid therein. Instructions of use and color strips showing outer appearance of the Transformable Pyramid may be printed on front and reverse surfaces of the eight faces of the carton. The carton therefore has the advantages of occupying a reduced space, and providing a fit package with instructions to facilitate display and promotion of the packaged goods.

Abstract: A sectional cubic block includes a plurality of layers of structural elements, a smallest one of which is an elementary cube and the other ones are proportionally increased in dimensions based on the elementary cube and all include three plane walls that separately extend in directions of x, y and z axes and therefore define an inner space adapted to receive a next smaller structural elements therein. Each of the structural elements, except the smallest one, is formed from a plurality of elementary frames sequentially proportionally increased in dimensions based on the elementary cube. Each of the elementary frames includes three continued right-angled parts that are respectively included in three planes extended in the directions of x, y and z axes. This particular configuration of the elementary frames enables children to freely stack the elementary frames to create many changeful shapes.