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Presents activities that engage students and promote discussion emphasizing the history of mathematics, diversity, and multiculturalism. Six activities included are Crossword Puzzle, Date of Event, Quotes Matching, Famous Mathematical Expressions, Calendar Scramble, and Map Puzzle. Also lists related World Wide Web sites. Contains 15 references. (Author/ASK)

Given an m x n array of k single random error correction (or erasure) codewords, each having length l such that mn = kl, we construct optimal interleaving schemes that provide the maximum burst error correction power such that an arbitrarily shaped error burst of size t can be corrected for the largest possible value of t. We show that for all such m x n arrays, the maximum possible interleaving distance, or equivalently, the largest value of t such that an arbitrary error burst of size up to t can be corrected, is bounded by [??][summation of 2k][??] if k [less than or equal to] [??]min{m,n})2/2[??], and by min{m,n} + [??]k - [??](min{m,n})2/2[??])/min{m,n}[??] if k [greater than or equal to] [??](min{m,n})2/2[??]. We generalize the cyclic shifting algorithm developed by the authors in a previous paper and construct, in several special cases, optimal interleaving arrays achieving these upper bounds. Additionally, for codewords of variable lengths, we solve a related array coloring problem for which the same upper bounds hold and can he achieved. Index Terms--Cluster errors, cyclic shifting, interleaving, random error-correcting codes, sphere packing.